Unfortunately but predictably, new solutions to the old problems brought new problems that in some ways were more complicated than the old ones. The societies of the United States and most other nations prominent in world affairs had to shoulder the enormous costs of standing military forces and modernization of rapidly changing technology. In the inflationary 1970s those costs would mean unpleasant choices of priorities in both internal and external affairs.
In some cases, as in Korea, the use of military force, despite critics on both ends of the political spectrum, was supported by most Americans as justified and, if not conclusive, at least an effective application of American power in pursuit of the Cold War goal of containment of communism. In other cases, such as the war in Vietnam, the prolonged and seemingly ineffective use of force destroyed the Cold War consensus, divided the nation, and contributed to moral and political uncertainty. For many Americans the protracted and ultimately unsuccessful involvement in Vietnam destroyed the Cold War consensus that containment of communist influence justified paying any price and bearing any burden anywhere in the world. In the face of the uncensored image of war, many in the United States rejected the idea of using force to destroy what one was trying to save.
In the years following the Vietnam War, American public attitudes regarding the use of force in foreign relations reflected what was termed, usually by its detractors, the Vietnam syndrome, or neo-isolationism—a reluctance to commit American power and prestige abroad. In the face of public and congressional resistance, American foreign policymakers felt obliged to pursue power politics in a more circumspect and sometimes secret manner. A policy of covert or deniable applications of power, dating back at least to Dwight D. Eisenhower's "hidden hand" presidency of the 1950s, was revived in the 1980s under President Ronald Reagan. Through circuitous and even questionable routes, American support went to anti-Sandinista contras in Nicaragua and anti-Soviet rebels in Afghanistan.
The danger of direct military intervention was dramatically brought home in 1983 by the deaths at the hands of a terrorist bomber of 241 U.S. marines who had been dispatched to Lebanon to protect an airfield in the midst of renewed Arab-Israeli fighting. The U.S. invasion of the Caribbean island of Grenada a few days later was an easy military victory, but it had little foreign policy significance. Perceived threats by anti-American regimes such as the one in Grenada might be dealt with effectively by decisive and "surgical," or specifically targeted, military intervention. But terrorist violence frustrated attempts at retaliation at an elusive, often unknown enemy.
By the 1990s Americans had discovered that in some ways the resort to force was achieving less and less. The Cold War, which had cost trillions in military spending on both sides, ended not by military victory but as a result of the Soviet Union's political and economic collapse. The breakup of the Soviet empire appeared to have left the United States the victor by default. But the world's only remaining superpower still found that its power did not necessarily guarantee hegemony or control over world politics.
In the Gulf War of 1991, the single most massive application of U.S. military force in the post–Cold War era, the United States, in partnership with Arab and European allies, successfully expelled Iraqi forces from Kuwait. But that tactical military success did not translate into significant changes in the geopolitical power relationships in the region. At the time, President George H. W. Bush pointed to the stunning military victory and the successful coalition diplomacy as evidence that America had "kicked the Vietnam syndrome." Yet that same victorious commander in chief was voted out of the presidency the following year. Short-term military success—the effective use of force—did not necessarily mean political success either abroad or at home.