The End of the Cold War - AP U.S. History

SECTION 1

Historical Context & Motivation

For over four decades, the Cold War between the United States and the Soviet Union defined international relations, domestic politics, and the global balance of power. From the Truman Doctrine of 1947 through the proxy wars and arms race of subsequent decades, both superpowers committed enormous economic and military resources to ideological competition. By the late 1970s, however, the strategic landscape was shifting: the Soviet economy was stagnating under the weight of centralized planning and military expenditure, while the United States experienced its own crises of confidence following Vietnam and Watergate. The election of Ronald Reagan in 1980 marked a renewed commitment to confronting Soviet power, setting the stage for a final, transformative chapter in superpower rivalry.

1979 • Soviet Invasion of Afghanistan

The Soviet Union's intervention in Afghanistan provoked international condemnation, a U.S. grain embargo, and a boycott of the 1980 Moscow Olympics, signaling the collapse of détente.

1983 • SDI and Escalation

Reagan announced the Strategic Defense Initiative, a proposed missile defense system that alarmed Soviet leaders and intensified the arms race, straining the USSR's already weakened economy.

1985 • Gorbachev Rises to Power

Mikhail Gorbachev became General Secretary of the Communist Party and introduced glasnost (openness) and perestroika (restructuring), fundamentally altering Soviet domestic and foreign policy.

1989 • Fall of the Berlin Wall

On November 9, East German authorities opened the Berlin Wall, symbolizing the disintegration of communist control over Eastern Europe and the approaching end of the Cold War.

1991 • Dissolution of the USSR

On December 25, Gorbachev resigned as president of the Soviet Union. The USSR formally dissolved into fifteen independent republics, ending the Cold War.

The central question for AP U.S. History students is not merely what happened, but why the Cold War ended when it did and how American policy choices intersected with internal Soviet dynamics. Was the end primarily driven by Reagan's military buildup, Gorbachev's reforms, structural economic failures within the Soviet system, or some combination of all three? Understanding these causal factors is essential for crafting strong analytical arguments on the AP exam.

SECTION 2

Core Principles & Key Concepts

The end of the Cold War cannot be attributed to a single cause; rather, it resulted from the convergence of several interconnected developments in U.S. foreign policy, Soviet internal reform, economic pressures, and grassroots movements across Eastern Europe. The following core principles provide an analytical framework for understanding how these forces interacted to produce one of the most significant geopolitical transformations of the twentieth century.

Reagan's Military Buildup

The Reagan administration dramatically increased defense spending—including the Strategic Defense Initiative—placing enormous economic pressure on the Soviet Union to match American military capabilities, ultimately accelerating Soviet economic decline.

Glasnost & Perestroika

Gorbachev's twin reforms of political openness (glasnost) and economic restructuring (perestroika) were intended to revitalize the Soviet system, but instead unleashed forces of nationalism and dissent that the Communist Party could not control.

Arms Control Diplomacy

A series of summit meetings between Reagan and Gorbachev—Reykjavík (1986), Washington (1987), Moscow (1988)—produced the INF Treaty and established a framework of mutual trust that facilitated the peaceful resolution of superpower tensions.

Eastern European Revolutions

Popular movements in Poland (Solidarity), Czechoslovakia (Velvet Revolution), Hungary, and East Germany challenged communist rule from below. Gorbachev's refusal to use force to prop up satellite states—abandoning the Brezhnev Doctrine—allowed these revolutions to succeed.

Soviet Economic Collapse

Structural inefficiencies in central planning, declining oil revenues, the enormous cost of the Afghan war, and the burden of matching U.S. defense spending combined to push the Soviet economy toward collapse, undermining the legitimacy of the communist system.

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KEY TAKEAWAY

Think of the Cold War's end like the failure of a dam under simultaneous pressures: American military spending applied force from one side, internal Soviet economic decay eroded the structure from within, Gorbachev's reforms opened controlled channels that became uncontrollable breaches, and popular movements in Eastern Europe crashed against the weakened barrier from the other side. No single pressure was sufficient alone—it was the convergence of external and internal forces that produced the collapse.

SECTION 3

Visual Explanation: Causal Forces

This diagram illustrates the five major causal forces converging on the end of the Cold War. Note the interconnections: Reagan's military buildup (blue) exacerbated Soviet economic decline (amber), while Gorbachev's reforms (violet) inadvertently empowered popular revolutionary movements (pink). Arms control diplomacy (green) provided the mechanism for peaceful resolution.

The diagram above reveals the deeply interconnected nature of the Cold War's conclusion. American military pressure did not operate in isolation; it was most effective because it exploited structural weaknesses already present in the Soviet economy. Similarly, Gorbachev's reforms were a response to both internal economic stagnation and external pressure, but they created unintended consequences—particularly the empowerment of nationalist and democratic movements in Eastern Europe—that ultimately proved fatal to communist control. The dashed lines in the diagram highlight these feedback loops: military spending worsened the economic crisis, and reform unleashed forces that could not be contained. For the AP exam, demonstrating an understanding of these causal relationships, rather than simply listing events, is essential for earning top scores on document-based and long essay questions.

SECTION 4

How the Cold War Ended: Key Mechanisms

The Reagan Doctrine and the "Peace Through Strength" Approach

Upon taking office in January 1981, Reagan rejected the détente framework that had characterized Nixon and Carter-era foreign policy, instead pursuing a strategy of aggressive confrontation with the Soviet Union. Defense spending increased by approximately 35 percent during his first term, funding new weapons systems such as the B-1 bomber, MX intercontinental ballistic missiles, and a 600-ship Navy. The most consequential initiative was the Strategic Defense Initiative (SDI), announced in March 1983, which proposed a space-based missile defense system capable of intercepting Soviet nuclear warheads. Although critics dismissed SDI as technologically unfeasible—earning it the nickname "Star Wars"—it profoundly alarmed Soviet leadership, which recognized that matching such a program would be financially ruinous. The Reagan Doctrine further extended this confrontation by providing covert and overt support to anti-communist insurgencies in Afghanistan, Nicaragua, Angola, and Cambodia, forcing the Soviet Union to defend its global commitments at enormous cost.

Gorbachev's Reforms and Their Unintended Consequences

When Mikhail Gorbachev assumed power in 1985, he inherited a Soviet system burdened by economic stagnation, technological backwardness, and a costly quagmire in Afghanistan. His response was twofold. Perestroika sought to restructure the Soviet economy by introducing limited market mechanisms and decentralizing decision-making, while glasnost encouraged political transparency and freedom of expression. Gorbachev believed these reforms would reinvigorate socialism, not destroy it. However, glasnost allowed citizens to openly criticize the government and the Communist Party for the first time, while perestroika disrupted existing economic networks without creating viable replacements. The result was a paradox: the very reforms designed to save the Soviet system accelerated its disintegration by empowering nationalist movements in the Baltic states, Ukraine, and the Caucasus, and by demonstrating to Eastern European satellite states that Moscow would no longer use military force to maintain communist governments.

Diplomacy and Arms Control

Despite Reagan's initial confrontational posture, his second term witnessed a dramatic pivot toward diplomacy following Gorbachev's ascension. Four summit meetings between 1985 and 1988 produced the landmark Intermediate-Range Nuclear Forces (INF) Treaty of 1987, which eliminated an entire class of nuclear weapons—all ground-launched ballistic and cruise missiles with ranges between 500 and 5,500 kilometers. This was the first treaty to actually reduce, rather than merely limit, nuclear arsenals. Reagan's successor, George H.W. Bush, continued this diplomatic trajectory with notable restraint, avoiding triumphalist rhetoric during the fall of the Berlin Wall and managing German reunification through careful multilateral negotiations. Bush's measured approach was critical: by declining to humiliate a collapsing Soviet Union, he helped ensure that the Cold War ended peacefully rather than in a desperate military confrontation.

SECTION 5

Detailed Breakdown: Pivotal Events 1985–1991

This vertical timeline traces the acceleration of Cold War dissolution from 1985 to 1991. The widening colored bars represent the growing momentum toward the end of the Soviet system, from early diplomatic overtures through revolutionary upheaval to final collapse.

Event	Date	Significance for AP Exam
Geneva Summit	Nov 1985	First Reagan-Gorbachev meeting; established personal rapport that enabled future agreements
Reykjavík Summit	Oct 1986	Nearly achieved total nuclear disarmament; collapsed over SDI disagreement but demonstrated willingness to negotiate
INF Treaty	Dec 1987	First treaty to eliminate an entire class of nuclear weapons; demonstrated that arms reduction, not just limitation, was possible
Fall of the Berlin Wall	Nov 1989	Symbolized the collapse of communist authority in Eastern Europe; test whether Bush would respond with restraint or triumphalism
German Reunification	Oct 1990	Demonstrated that Cold War divisions were being resolved through diplomacy; required negotiations with both USSR and European allies
Dissolution of USSR	Dec 1991	Formal end of the Cold War; United States emerged as the sole superpower, raising debates about the "new world order" and American global role

Key events in the dissolution of the Cold War order, 1985–1991

SECTION 6

Worked Example: Analyzing a Primary Source

AP U.S. History frequently requires students to analyze primary source documents within their historical context. Below is a worked example demonstrating how to approach a passage from Reagan's 1987 Brandenburg Gate speech and construct a historically grounded analytical response.

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SOURCE EXCERPT

"General Secretary Gorbachev, if you seek peace, if you seek prosperity for the Soviet Union and Eastern Europe, if you seek liberalization: Come here to this gate! Mr. Gorbachev, open this gate! Mr. Gorbachev, tear down this wall!" — Ronald Reagan, Brandenburg Gate, West Berlin, June 12, 1987

Analyzing Reagan's Brandenburg Gate Speech (SAQ Format)

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Step 1 — Identify Historical Context

Situate the speech within the broader trajectory of Cold War diplomacy in the late 1980s. By June 1987, Reagan and Gorbachev had already met at Geneva (1985) and Reykjavík (1986), and the INF Treaty was under negotiation. Gorbachev's reforms of glasnost and perestroika were underway, and the political climate in Eastern Europe was increasingly unstable. Reagan delivered this speech just months before signing the INF Treaty, suggesting that his rhetoric combined confrontation with engagement.

Context: Delivered during a period of active U.S.-Soviet diplomacy and internal Soviet reform, the speech reflects Reagan's strategy of pressuring Gorbachev publicly while negotiating privately.
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Step 2 — Analyze the Audience and Purpose

Reagan's immediate audience was the West Berlin crowd, but the speech was also directed at the American public, Western European allies, East Germans, and the Soviet leadership. The rhetorical demand to "tear down this wall" served multiple purposes: it reinforced American moral leadership, signaled to Gorbachev that the United States expected concrete action to match reformist rhetoric, and inspired democratic aspirations in Eastern Europe. Note that many of Reagan's own advisors initially opposed the line, fearing it was too provocative; Reagan's insistence on keeping it reveals the deliberate nature of his confrontational rhetoric.

Purpose: Multi-layered—domestic rallying cry, diplomatic pressure on Gorbachev, and inspiration for Eastern European reform movements.
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Step 3 — Evaluate Historical Significance

At the time, the speech received relatively modest media attention and was not treated as a landmark moment. Its significance grew retroactively after the Wall fell in November 1989, when it became a symbol of American resolve and Reagan's prophetic vision. For the AP exam, this is a critical distinction: the historical significance of an event or document is often constructed after the fact. A strong response would note that while Reagan's words did not directly cause the Wall's fall, the speech exemplifies the broader American strategy of maintaining ideological pressure on the Soviet system during a period of internal vulnerability.

Significance: Retrospectively iconic; demonstrates how historical memory shapes the perceived importance of events.
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Step 4 — Connect to Broader Themes

Link the speech to AP themes such as American identity (the role of the U.S. as a defender of freedom), politics and power (presidential rhetoric as a tool of foreign policy), and America in the world (the tension between idealism and pragmatism in Cold War diplomacy). A top-scoring response would argue that Reagan's speech encapsulates the dual-track strategy of military buildup and diplomatic engagement that characterized the final phase of the Cold War.

Thematic connections: American identity, presidential power, and the tension between idealism and realism in foreign policy.

SECTION 7

Competing Historiographical Interpretations

Historians disagree about who or what "won" the Cold War, and this debate frequently appears in AP exam essays. Understanding competing interpretations allows students to construct more nuanced arguments and engage with the complexity of historical causation.

Interpretation	Key Argument	Limitations
Triumphalist / Conservative	Reagan's military buildup and ideological confrontation forced the Soviet Union into economic collapse; American strength and moral clarity won the Cold War.	Underestimates internal Soviet factors; the USSR's problems predated Reagan; ignores Gorbachev's agency in choosing reform over repression.
Structural / Economic	The Soviet command economy was inherently unsustainable; declining oil revenues and the costs of the Afghan war would have caused collapse regardless of U.S. policy.	Difficult to explain the precise timing; other authoritarian states have survived economic crises; doesn't account for Gorbachev's specific policy choices.
Gorbachev-centric	Gorbachev's personal leadership was decisive: he chose reform over repression and refused to use force to maintain the Soviet empire, enabling a peaceful transition.	Overemphasizes individual agency; Gorbachev's reforms often produced unintended consequences rather than deliberate outcomes.
"People Power" / Bottom-Up	Popular movements—Solidarity in Poland, the Velvet Revolution in Czechoslovakia, mass protests in East Germany—drove the end of communism from below, not from superpower decisions above.	These movements succeeded partly because Gorbachev chose not to intervene; similar uprisings in 1956 (Hungary) and 1968 (Czechoslovakia) were crushed.

Major historiographical interpretations of the Cold War's end

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KEY TAKEAWAY

On the AP exam, the strongest essays do not commit to a single interpretation but instead synthesize multiple causal factors into a coherent argument. Think of it like a medical diagnosis: a patient may have several contributing conditions, and the best physician identifies how they interact rather than attributing illness to a single cause. Similarly, the best historical arguments recognize the interplay between American foreign policy, Soviet internal dynamics, individual leadership, and popular movements.

SECTION 8

Legacy and Connection to the Post–Cold War Era

The end of the Cold War did not simply resolve an old conflict; it created an entirely new set of challenges and debates that continue to shape American politics and foreign policy. Understanding these legacies is essential for connecting Period 9 content to the broader themes tested on the AP exam.

Cold War Era	Post–Cold War Era
Bipolar world order: U.S. vs. USSR	Unipolar moment: U.S. as sole superpower; debates over "new world order"
Containment doctrine guided foreign policy	No clear replacement doctrine; debates over humanitarian intervention, nation-building, and unilateralism
Nuclear arms race as central security concern	Nuclear proliferation, terrorism, and non-state actors become primary threats
Defense spending justified by Soviet threat	"Peace dividend" debate: redirect military spending to domestic priorities?
Bipartisan anti-communist consensus	Increased partisan polarization over foreign policy direction

Transition from Cold War to post–Cold War dynamics

George H.W. Bush articulated the concept of a "new world order" in which international cooperation through institutions like the United Nations would replace superpower rivalry as the organizing principle of global politics. The 1991 Gulf War seemed to validate this vision, as a broad international coalition liberated Kuwait under UN authorization. However, subsequent crises—including the Balkans wars, the Rwandan genocide, and the rise of international terrorism culminating in the September 11, 2001 attacks—revealed the limitations of this optimistic framework. The unipolar moment generated intense debate about whether the United States should serve as the world's policeman or retrench to focus on domestic concerns—a debate that remains unresolved and continues to inform contemporary political discourse.

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AP EXAM TIP

The College Board frequently tests the concept of continuity and change over time in relation to the Cold War's end. A strong long essay or DBQ response would identify both what changed (bipolar order dissolved, new security threats emerged) and what continued (debates over American global role, tension between military and diplomatic approaches, disagreements about defense spending priorities).

SECTION 9

Practice Problems

Question 1: CONCEPTUAL

Which of the following best explains why Gorbachev's policy of glasnost contributed to the dissolution of the Soviet Union?

A. It allowed Western corporations to invest directly in the Soviet economy, undermining state control over production.
B. It permitted open criticism of the government and Communist Party, emboldening nationalist movements and public dissent that the state could not contain.
C. It eliminated censorship of foreign media, which led Soviet citizens to adopt capitalist economic practices.
D. It transferred political power from the Communist Party to regional military commanders, who then declared independence.

Show answer (B)

B is correct. Glasnost (openness) relaxed political censorship and allowed Soviet citizens to publicly criticize the government for the first time. This unleashed nationalist movements in the Baltic states, Ukraine, and other republics, as well as broader public demands for reform that exceeded what Gorbachev intended. A is incorrect because glasnost was a political transparency policy, not an economic investment program. C is incorrect because while media restrictions loosened, the primary effect was political dissent rather than adoption of capitalist practices. D is incorrect because glasnost did not transfer power to military commanders; independence movements were led by civilian political leaders and popular movements.

Question 2: BASIC CALCULATION

The Intermediate-Range Nuclear Forces (INF) Treaty of 1987 was historically significant primarily because it

A. established the framework for the Strategic Defense Initiative.
B. was the first arms control agreement to eliminate an entire class of nuclear weapons rather than merely limiting their growth.
C. banned all nuclear weapons testing, building on the precedent of the Limited Test Ban Treaty.
D. required the Soviet Union to withdraw all military forces from Eastern Europe.

Show answer (B)

B is correct. The INF Treaty was groundbreaking because it required both the U.S. and USSR to destroy all ground-launched ballistic and cruise missiles with ranges of 500–5,500 kilometers—the first time an arms control agreement mandated the elimination of an entire weapons category rather than capping production. A is incorrect because SDI was a unilateral U.S. initiative, not a treaty framework. C is incorrect because the INF Treaty addressed deployed weapons, not nuclear testing; the Comprehensive Nuclear-Test-Ban Treaty (1996) addressed testing. D is incorrect because the treaty dealt specifically with intermediate-range missiles, not with conventional military deployments in Eastern Europe.

Question 3: INTERMEDIATE

3 pts

Answer parts (a), (b), and (c). (a) Briefly describe ONE specific action taken by the Reagan administration to increase pressure on the Soviet Union during the 1980s. (b) Briefly explain ONE way in which Gorbachev's reforms of glasnost and perestroika had unintended consequences that contributed to the end of the Cold War. (c) Briefly explain ONE reason why George H.W. Bush's response to the fall of the Berlin Wall in 1989 was significant for U.S. foreign policy.

Show answer

Point-by-Point Rubric: (a) 1 point: Acceptable responses include: the announcement of the Strategic Defense Initiative (SDI) in 1983, which proposed a space-based missile defense system that the Soviets could not afford to match; the massive increase in defense spending (approximately 35% increase in Reagan's first term); support for anti-communist insurgencies under the Reagan Doctrine (e.g., funding the mujahideen in Afghanistan, supporting the Contras in Nicaragua); or the deployment of Pershing II missiles in Western Europe. The response must identify a specific action and briefly describe it. (b) 1 point: Acceptable responses must explain how reforms designed to strengthen the Soviet system instead weakened it. For example: glasnost allowed open criticism of the Communist Party and Soviet history, which emboldened nationalist movements in the Baltic states, Ukraine, and other republics that demanded independence; or perestroika disrupted existing economic networks without creating effective market replacements, worsening economic conditions and public dissatisfaction. The response must go beyond naming the reform to explain the unintended consequence. (c) 1 point: Acceptable responses should explain that Bush deliberately avoided triumphalist rhetoric following the Wall's fall, choosing measured diplomacy over celebration. This was significant because: it avoided provoking hardliners within the Soviet military or government who might have reversed reforms or resorted to violence; it preserved the cooperative relationship with Gorbachev that was essential for managing German reunification and further arms reduction; or it demonstrated a pragmatic approach to foreign policy that prioritized stability over ideological posturing.

Question 4: APPLIED

4 pts

Using the two documents below, answer the following: Evaluate the extent to which Reagan's foreign policy was responsible for ending the Cold War. Document 1: Excerpt from President Reagan's "Evil Empire" speech to the National Association of Evangelicals, March 8, 1983: "I urge you to beware the temptation of pride—the temptation of blithely declaring yourselves above it all and label both sides equally at fault, to ignore the facts of history and the aggressive impulses of an evil empire, to simply call the arms race a giant misunderstanding and thereby remove yourself from the struggle between right and wrong and good and evil." Document 2: Excerpt from Mikhail Gorbachev's Nobel Peace Prize lecture, June 5, 1991: "The Cold War is over. The risk of a global nuclear war has practically disappeared. The iron curtain is gone... This is a joint victory that we have won through joint efforts... No one side can claim credit for what has happened."

Show answer

Point-by-Point Rubric (4 points): Thesis (1 point): Must present a historically defensible claim that evaluates the extent of Reagan's responsibility. A strong thesis would argue something like: "While Reagan's military buildup and ideological confrontation placed significant economic and diplomatic pressure on the Soviet Union, the Cold War's end resulted primarily from the convergence of American policy with internal Soviet factors—particularly Gorbachev's reforms and structural economic decline—rather than from U.S. actions alone." The thesis must take a clear position and establish a line of reasoning. Document Analysis (1 point): Must accurately use BOTH documents to support the argument. Document 1 reveals Reagan's framing of the Cold War in moral and ideological terms, rejecting moral equivalence and justifying confrontation. This can be used to support the argument that Reagan's ideological pressure contributed to Soviet decline. Document 2, from Gorbachev, explicitly rejects the idea that one side "won," framing the Cold War's end as a "joint victory." This can be used as evidence that Reagan's role, while significant, was only part of a larger set of causes. Sourcing/Context (1 point): Must analyze the historical context, audience, purpose, or point of view of at least one document. For Document 1: Reagan spoke to a religious audience and framed the Cold War in moral terms to build domestic support for increased defense spending and an anti-détente foreign policy; his purpose shapes the absolutist language. For Document 2: Gorbachev had strong personal and political reasons to reject the "triumphalist" narrative—as the leader who presided over the USSR's dissolution, framing the outcome as mutual preserved his legacy and dignity. Outside Evidence (1 point): Must incorporate at least one piece of relevant historical evidence not found in the documents. Examples include: the specific role of the Strategic Defense Initiative in straining the Soviet economy; the INF Treaty of 1987 as evidence of diplomatic engagement; the Solidarity movement in Poland as evidence of bottom-up popular pressure; the Soviet war in Afghanistan as a drain on Soviet resources; or George H.W. Bush's restrained response to the fall of the Berlin Wall.

Question 5: CRITICAL THINKING

4 pts

Evaluate the extent to which the end of the Cold War represented a turning point in the United States' role in global affairs. In the development of your argument, explain what changed and what stayed the same from the period before the Cold War ended to the period after.

Show answer

Point-by-Point Rubric (4 points): Thesis (1 point): Must present a historically defensible thesis that addresses the extent of change. A strong thesis might argue: "The end of the Cold War was a significant but incomplete turning point in America's global role: while it transformed the strategic framework from bipolar containment to unipolar predominance and introduced new security challenges like terrorism and humanitarian intervention, it did not fundamentally alter the underlying debate between interventionism and restraint that has characterized American foreign policy since World War II." Contextualization (1 point): Must situate the argument within broader historical developments. This could include: the containment doctrine (Truman Doctrine, NSC-68) that defined the Cold War era; the shift from détente to renewed confrontation under Reagan; the long arc of American debate between isolationism and internationalism stretching back to the interwar period; or the economic dimensions of superpower competition. Evidence (1 point): Must use specific historical evidence to support the argument. Changes: the dissolution of the USSR eliminated the organizing principle of containment; Bush's "new world order" speech proposed multilateral cooperation as a replacement framework; the Gulf War (1991) demonstrated unilateral American military dominance; new threats like international terrorism replaced the Soviet threat (9/11, War on Terror). Continuities: the defense budget remained enormous even after the "peace dividend" debate; NATO expanded rather than dissolving; debates over American intervention continued (Somalia, Bosnia, Kosovo); partisan disagreements over foreign policy persisted. Analysis (1 point): Must demonstrate complex understanding by analyzing both change and continuity, and by explaining why the identified changes and continuities are historically significant. A sophisticated response would argue that while the Cold War's end transformed the structure of international relations, American foreign policy behavior—characterized by military interventionism, alliance management, and ideological projection—showed remarkable continuity, suggesting that American global engagement was driven by deeper structural factors than the specific existence of a Soviet adversary.

SUMMARY

Summary: The End of the Cold War

Summary

The end of the Cold War resulted from the convergence of multiple forces between 1980 and 1991. Reagan's military buildup and the Strategic Defense Initiative placed enormous economic pressure on the Soviet Union, while the Reagan Doctrine supported anti-communist movements worldwide. Gorbachev's twin reforms of glasnost and perestroika were intended to revitalize the Soviet system but instead empowered nationalist movements and public dissent that the Communist Party could not control. A series of summit meetings produced the INF Treaty—the first agreement to eliminate an entire class of nuclear weapons—while popular revolutions swept across Eastern Europe in 1989, symbolized by the fall of the Berlin Wall.

President George H.W. Bush managed the final stages with diplomatic restraint, facilitating German reunification and avoiding provocations that might have triggered a violent backlash. The dissolution of the Soviet Union on December 25, 1991, left the United States as the world's sole superpower, inaugurating debates over the "new world order", the peace dividend, and America's proper role in a post–Cold War world. For the AP exam, remember that the strongest analytical arguments synthesize multiple causal factors—American military pressure, Soviet internal decay, individual leadership, and popular movements—rather than attributing the outcome to any single cause.