But even the president seemed skeptical about how positive an outcome can be achieved. Despite the high human and financial sacrifices America will pay by staying in Iraq, the president believes the United States must do so because the consequences of withdrawing will be even more costly. Bush himself stated pointedly: "Failure in Iraq would be a disaster for the United States."

It is clear that the president sees Iraq as playing a key role in the war on terror. At the very beginning of his address, he said, "Tonight in Iraq, the armed forces of the United States are engaged in a struggle that will determine the direction of the global war on terror." He sees the two as intertwined: victory in Iraq will allow victory in the war on terror, while withdrawal from Iraq will lead to dire consequences in the larger struggle.

But as the 2006 midterm congressional election results and public opinion polls have shown, the American public is increasingly weary of the war in Iraq and skeptical about the possibility of "victory" there. Congressional leaders are talking about denying funds for the president's surge strategy. There is a real possibility that Congress, under pressure from the public, will force the United States to withdraw from Iraq after or even before the 2008 U.S. elections, just like it forced an American withdrawal from Vietnam in the early 1970s.

Under these circumstances, will America inevitably face the dire consequences that President Bush predicts that withdrawal from Iraq will lead to? The Vietnam experience illuminates this question.

Negative consequences certainly did result from the American withdrawal from Vietnam. Communist forces took over not only South Vietnam, but also Laos and Cambodia. In addition, Marxist revolutionaries came to power in many Third World countries during the 1970s, including in Ethiopia, Angola, Mozambique, Afghanistan, Nicaragua, and elsewhere.

These revolutions were facilitated by the U.S. withdrawal from Vietnam since it made clear to Marxists elsewhere that the United States was unlikely to intervene against them. By the time the Soviets invaded Afghanistan in 1979, America's position in the world appeared weak. Chinese-American relations had improved dramatically, but this occurred mainly because Beijing no longer feared the United States but did fear the Soviet Union.

Despite all this, communism collapsed in Eastern Europe ten years later in 1989. The Soviet Union fell apart at the end of 1991. Most Marxist regimes in the Third World either fell (as in Ethiopia, Afghanistan and Nicaragua) or normalized their relations with the United States (as with Angola, Mozambique, and Vietnam itself). Marxist regimes hostile to the United States have remained in power only in Cuba and North Korea. While not without tension, Chinese-American relations have blossomed despite the demise of their common Soviet enemy.

Thus, America's "failure" in Vietnam and elsewhere in the Third World did not prevent it from prevailing in the Cold War. Indeed, the two events were related: The American withdrawal from Vietnam served to encourage the Soviet Union and its allies to overextend themselves in the Third World, and this in turn contributed to the collapse of communism. At the time, of course, nobody foresaw this. Yet this is what occurred.

What this suggests is that an American "failure" in Iraq will indeed lead to negative consequences. It would, as President Bush predicted, put radical Islamic forces "in a better position to topple moderate governments." They would certainly try to do this.

One of two things would then happen: 1) Fearing the consequences of Islamist rule, some populations will rally to their governments -- and to the United States -- in order to prevent it; or 2) The Islamists will succeed in coming to power in some countries, proceed to misrule them and attempt to spread revolution to others, becoming vulnerable through overextension themselves.

And if Islamist groups become hostile to each other (as Sunni and Shiite radicals are in Iraq), one or both sides in these disputes may eventually turn to America for help against the other no matter how anti-American they are now -- just as the anti-American Soviet and Chinese communists eventually did when their dispute with each other grew intense.

Just as the U.S. withdrawal from Vietnam did not prevent America from prevailing in the Cold War, a U.S. withdrawal from Iraq will not prevent America from prevailing in the war on terror. It would be wonderful if the new strategy announced by President Bush brings peace and prosperity to Iraq. However, if it does not and Congress forces the United States to withdraw, the negative consequences that ensue may not be as bleak as President Bush believes. Just as in the Cold War, America may be able to wage the war on terror more easily when it is no longer overextended but its opponents are.

Deliberately withdrawing in anticipation of one's opponents becoming overextended and vulnerable is obviously not the strategy that Bush, or any American president, would choose. It is the strategy, though, that the logic of the situation may force upon him and/or his successors, just as it did upon Nixon, Ford, and theirs.

Mark N. Katz is a professor of government and politics at George Mason University

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