The Cold War ended through a mix of political, economic, and diplomatic factors—not one single event. Key causes: Reagan’s military buildup and diplomatic pressure (Reagan Doctrine, SDI), Gorbachev’s reforms (glasnost and perestroika), arms-control treaties (INF, START I), and popular revolutions across the Eastern Bloc in 1989 (including the fall of the Berlin Wall). Those pressures led to the collapse of the Warsaw Pact, German reunification (1990), and political breakdown inside the USSR. The Cold War’s formal endpoint is usually dated to the dissolution of the Soviet Union: the Soviet parliament voted the USSR out of existence on December 26, 1991. For AP study, tie causes (Reagan policies, Gorbachev, economic problems, 1989 revolutions) to effects (new U.S. roles, peacekeeping debates) as the CED requires. Review Topic 9.3 study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg) and practice problems (https://library.fiveable.me/practice/ap-us-history).

Reagan spent heavily on the military even though he said he wanted peace because he believed peace came from strength. His 1980s buildup (nuclear and conventional forces, plus the Strategic Defense Initiative) served to deter Soviet aggression, back the Reagan Doctrine’s support for anti-communist movements, and create bargaining leverage in arms talks (INF, START I). Economically and politically, massive U.S. spending worsened strains on the Soviet system—helping push Gorbachev toward glasnost and perestroika and making arms reductions more attractive. In short: the buildup was meant to prevent war by making confrontation costly and to pressure the USSR into negotiation and reform—outcomes tied directly to KC-9.3.I.A and I.B in the AP CED. For more on Topic 9.3, see the Fiveable study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg) and practice questions (https://library.fiveable.me/practice/ap-us-history).

Reagan’s speeches mattered because they combined firm public pressure with clear policy signals. He labeled the USSR an “evil empire,” publicly asserted U.S. opposition to communism (Reagan Doctrine), and promoted military strength (big defense buildup and the Strategic Defense Initiative)—that raised the stakes and signaled the U.S. wouldn’t accept Soviet expansion. His 1987 Berlin line, “Mr. Gorbachev, tear down this wall,” mattered symbolically: it put Soviet repression on the world stage and encouraged dissidents in Eastern Europe. Those rhetoric moves pressured Soviet leaders politically while U.S. diplomacy (summits with Mikhail Gorbachev) and treaties (INF, START I) offered a path to de-escalation. In AP terms, Reagan’s speeches are part of KC-9.3.I.A/B—they asserted opposition, supported increased military spending, and helped create conditions for glasnost/perestroika to succeed. For a short study review, see the Topic 9.3 study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg) and try practice problems (https://library.fiveable.me/practice/ap-us-history).

The Soviet economy was key to the Cold War’s end. By the 1970s–80s it faced chronic stagnation from inefficient central planning: low productivity, outdated industry, poor agriculture (shortages), and little technological innovation. High military spending—exacerbated by the U.S. defense buildup under Reagan and costly involvements like Afghanistan—drained resources. Falling world oil prices and rising foreign debt reduced hard-currency income. Gorbachev’s perestroika tried to reform the system but revealed deeper fiscal limits; glasnost exposed political and social unrest, weakening Communist control and encouraging Eastern Bloc revolutions (1989). These economic strains made sustained competition with U.S. military and economic power unsustainable, helping produce arms-control deals (INF, START) and ultimately the USSR’s dissolution. For AP review, see the Topic 9.3 study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg) and practice questions (https://library.fiveable.me/practice/ap-us-history).

Good question—it seems backwards at first. Reagan’s large military and programs like the Strategic Defense Initiative (SDI) didn’t create peace by themselves; they created pressure. By expanding nuclear and conventional arms spending and backing anti-communist initiatives (Reagan Doctrine), the U.S. forced the Soviet Union into an expensive arms race it couldn’t sustain alongside economic stagnation. That pressure, plus Gorbachev’s reforms (glasnost, perestroika), opened space for diplomacy (INF Treaty, START I) and political change across the Eastern Bloc—leading to events like the fall of the Berlin Wall and Soviet dissolution. So the buildup contributed indirectly: it raised costs and incentives for negotiation, not because more arms are peaceful, but because they changed the balance and political will. For AP exam prep, link this to KC-9.3.I.A–C and review the Topic 9.3 study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg). For practice, try problems at (https://library.fiveable.me/practice/ap-us-history).

Reagan broke with the more cautious Cold War approaches of his immediate predecessors by combining tougher rhetoric and a big military buildup with active support for anti-communist forces. Earlier presidents after Nixon/Ford/Carter mostly practiced containment and détente—limited engagement, arms control, and selective interventions. Reagan publicly called the USSR the "evil empire," launched the Strategic Defense Initiative, increased defense spending, and pushed the Reagan Doctrine (covert/conventional aid to anti-communist movements). At the same time he negotiated major arms deals with Mikhail Gorbachev (INF Treaty, later START I) and engaged diplomatically as Soviet glasnost and perestroika weakened communist control. That mix—pressure plus negotiation—accelerated the Eastern Bloc revolutions of 1989 and the Soviet collapse. For AP review, focus on Reagan’s military buildup, Reagan Doctrine, SDI, and arms treaties as causes/effects in Topic 9.3 (see the topic study guide: https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg). For extra practice, use unit review and practice questions (https://library.fiveable.me/ap-us-history/unit-9; https://library.fiveable.me/practice/ap-us-history).

Start with a tight thesis that answers “why the Cold War ended” and sets a line of reasoning (e.g., political/economic collapse in USSR, Gorbachev’s reforms, and U.S. pressure under Reagan). In your 1–2 sentence contextualization, situate the 1980s within the longer Cold War (arms race, proxy wars, détente). Use at least four documents to support separate parts of your argument (showing Reagan’s military buildup and diplomacy, Gorbachev’s glasnost/perestroika, Eastern Bloc unrest like Solidarity and 1989 revolutions). Include one specific piece of outside evidence (e.g., INF Treaty, fall of Berlin Wall, dissolution of USSR) and explain for two documents how POV/purpose/audience affect their usefulness. End by showing complexity—compare structural causes (economic decline) with policy choices (Reagan/Gorbachev) and note post-Cold War effects (new U.S. interventions). Remember DBQ rules: 15-minute reading period, use ≥4 docs, at least one outside fact, source two docs, and earn the thesis/context points. Review Topic 9.3 study guide for helpful facts (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg) and practice questions (https://library.fiveable.me/practice/ap-us-history).

Political changes in Eastern Europe that helped end the Cold War were mostly regime breakdowns and popular movements in 1989. Economic stagnation and loss of faith in communist systems—exacerbated by Gorbachev’s reforms (glasnost and perestroika) and his refusal to use force—encouraged dissident movements like Solidarity in Poland to push for free elections. In country after country (Poland, Hungary, Czechoslovakia, East Germany, Romania), governments either negotiated transitions or collapsed during the Eastern Bloc revolutions of 1989. The fall of the Berlin Wall and subsequent German reunification symbolized the unraveling of Soviet control; the Warsaw Pact dissolved soon after. These political shifts reduced Soviet influence, made superpower confrontation unnecessary, and opened the path to the Soviet Union’s own dissolution—key causes and effects you need to explain for CED Learning Objective C. For a focused review, see the Topic 9.3 study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg) and practice questions (https://library.fiveable.me/practice/ap-us-history).

Short answer: it did both. The Cold War’s end (Reagan pressure, Gorbachev’s glasnost/perestroika, arms agreements like INF and START, fall of the Berlin Wall, Soviet dissolution) reduced the bipolar nuclear standoff and large-scale U.S.–Soviet proxy wars, creating a more open global order and new diplomatic ties—that’s the peace side the CED asks you to explain (KC-9.3.I.A–C). But it also produced different problems: collapsed states and ethnic conflicts (Yugoslavia/Bosnia), messy peacekeeping and limited military interventions (Somalia, Bosnia), debates over U.S. use of power, NATO expansion, and new security threats like regional proliferation and transnational terrorism. So the legacy is mixed: less superpower confrontation but more regional instability and complex humanitarian missions. For a quick CED-aligned review, see the Topic 9.3 study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg) and try practice questions (https://library.fiveable.me/practice/ap-us-history) to prep for exam connections.

After the Cold War the U.S. shifted from superpower rivalry to more regional military and peacekeeping actions. Key examples: Somalia (UN-backed humanitarian/military mission, 1992–93), Haiti (1994 intervention to restore elected leaders), Bosnia (NATO/U.S. peacekeeping and air campaigns mid-1990s to enforce Dayton Accords), and Kosovo (1999 NATO air campaign and peacekeepers to stop ethnic cleansing). Later large-scale interventions include Afghanistan (2001) and Iraq (2003), which sparked big debates about when the U.S. should use force versus diplomacy—exactly the legacy the CED highlights (post-Cold War peacekeeping, Bosnia/Somalia). These episodes appear a lot on AP questions about causes/effects and U.S. global role—practice connecting events to continuity/change and debates over American power for short answers or LEQs. For a focused recap, see the Topic 9.3 study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg). For extra practice, try questions at (https://library.fiveable.me/practice/ap-us-history).

You “won” the Cold War, but that didn’t end debates about American power because victory created new questions, not answers. The U.S. emerged as the lone superpower (unipolarity), but the CED notes that the end of the Cold War led to “new diplomatic relationships” and “continued debates over the appropriate use of American power” (KC-9.3.I.C). Critics point to limits and costs of using hard power (Somalia 1992–94) and messy peacekeeping (Bosnia intervention, 1995), while others argue the U.S. should lead to protect global stability (NATO expansion, diplomacy with post-Soviet states). Debates focus on legality, ethics, effectiveness, and whether to use military force or diplomacy/economic tools (soft power). For AP prep, tie these causes/effects to Reagan, Gorbachev, glasnost/perestroika, and post-Cold War interventions. Review Topic 9.3 study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg) and practice questions (https://library.fiveable.me/practice/ap-us-history) to practice DBQ/LEQ connections.

Reagan’s diplomatic initiatives combined pressure and negotiation. He escalated military spending and promoted the Strategic Defense Initiative (SDI) to raise costs for the USSR (KC-9.3.I.A). The Reagan Doctrine backed anti-communist movements (e.g., support for Solidarity and anti-Soviet insurgents), increasing geopolitical pressure (KC-9.3.I.B). At the same time Reagan opened direct diplomacy with Mikhail Gorbachev through summit meetings (Geneva, Reykjavik, Washington), which led to the 1987 INF Treaty eliminating an entire class of nuclear missiles and set the stage for START I talks. Reagan’s mix of forceful rhetoric, economic and military pressure, and face-to-face diplomacy helped create conditions for Gorbachev’s glasnost and perestroika, the 1989 Eastern Bloc revolutions, and ultimately the Soviet collapse. For the AP exam, link these initiatives to KC-9.3.I.A–I.C and use the Topic 9.3 study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg). For extra practice, try problems at (https://library.fiveable.me/practice/ap-us-history).

When the Cold War ended, U.S. relationships shifted from bipolar rivalry to more varied roles. Politically and diplomatically the U.S. moved from containment to cooperation with former adversaries—e.g., diplomatic engagement with the Soviet leadership of Mikhail Gorbachev (glasnost, perestroika), arms agreements like the INF Treaty and START I, and support for German reunification after the fall of the Berlin Wall. Economically the U.S. expanded trade and globalization ties as former Eastern Bloc countries opened markets. Militarily the role changed: fewer superpower standoffs but more regional interventions and peacekeeping (Somalia, Bosnia), prompting debates about when to use U.S. power. The end also created new security challenges (ethnic conflicts, nuclear proliferation in former Soviet states) and new partnerships in NATO expansion. For AP exam prep, connect causes (Reagan buildup, Soviet weakness, Gorbachev reforms) to effects (new diplomacy, interventions, debates over power) to meet LO C in Topic 9.3—see the topic study guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg) and practice questions (https://library.fiveable.me/practice/ap-us-history).

When the Cold War ended the U.S. and the Soviet Union (and later Russia) started cutting nuclear forces through treaties and programs rather than destroying everything overnight. Key treaties—INF (1987) eliminated all U.S. and Soviet intermediate-range missiles; START I (1991) required deep cuts in strategic warheads and delivery systems—led to thousands of warheads being retired and delivery vehicles dismantled. The Nunn-Lugar Cooperative Threat Reduction program helped dismantle weapons and secure nuclear materials across the former USSR; Ukraine, Belarus, and Kazakhstan gave up Soviet warheads (Budapest Memorandum, 1994) and transferred them to Russia or had them dismantled. Many warheads were dismantled and fissile material stored or down-blended; others stayed in reserve or were removed from “hair-trigger” alert. Concerns about proliferation remained, but overall the post-Cold War era saw significant arms-control progress (INF, START) that fits directly into Topic 9.3’s causes and effects of the Cold War’s end (see KC-9.3.I.B and INF/START in the CED). For the topic study guide, check Fiveable’s Topic 9.3 guide (https://library.fiveable.me/ap-us-history/unit-9/end-cold-war/study-guide/jSK48CxJEPXM0bpeuKEg) and use practice questions (https://library.fiveable.me/practice/ap-us-history) for exam prep.