President George Bush surprised people on both sides of the Pacific when he ended Washington’s long-standing policy of “strategic ambiguity” regarding Taiwan.

Previously, U.S. leaders had indicated the United States would regard the use of force against Taiwan by the People’s Republic of China as a serious breach of the peace and might–depending on the circumstances–intervene militarily.

Bush discarded such nuances and stated bluntly that the United States would do whatever was necessary to defend Taiwan from attack. In making that statement, he replaced strategic ambiguity with strategic clarity. Unfortunately, he clarified matters in precisely the wrong direction.

Advocates of a hard-line policy toward the PRC applauded the president’s comments. But such endorsements reflect a lack of realistic thinking. Americans must ask themselves whether they would really be willing to risk confrontation with a nuclear-armed China over Taiwan.

That is especially pertinent as the PRC’s military capability–probably including a much larger and more modern strategic nuclear deterrent–increases over the next decade or two.

Proponents of giving Taiwan a security guarantee blithely assume that Beijing will back down if faced with a clear demonstration of American resolve, a lesson drawn almost entirely from America’s Cold War experience.

The conventional wisdom is that aggressors will be deterred from molesting a U.S. ally or client whenever Washington provides an unambiguous security commitment.

But the assumption that the deterrence of Soviet aggression during the Cold War can be replicated with regard to China and Taiwan is dubious. A strategy of deterrence is hardly infallible.

Indeed, history is littered with the wreckage of deterrence failures. Many Europeans in the early years of the 20th century assumed the continent’s elaborate system of alliances would make war unthinkable. The tragic events of 1914 demonstrated how wrong they were.

In addition to the balance of military power, three factors are especially important in determining whether deterrence is likely to succeed: the importance of the stakes to the protector, the importance of the stakes to the challenging power and the extent of the challenging power’s inclination to gamble. All three factors worked to Washington’s advantage to an unusual degree in its confrontation with the Soviet Union.

America’s Cold War security guarantees centered on Western Europe and Northeast Asia. Both regions were considered crucial to America’s own security and economic well-being. Kremlin leaders believed the United States would be willing to incur significant risks–even the possibility of nuclear war–to thwart a Soviet conquest.

But while those regions would have been significant strategic and economic prizes for the Soviet Union, Moscow had no emotional stake. There was, therefore, a definite limit to the risks the Kremlin was willing to run to gain dominion. Fortunately for the United States, the Soviet leadership also was relatively risk-averse. Most of Moscow’s challenges occurred on the periphery, primarily in the Third World.

There are crucial differences in all three deterrence factors when it comes to a showdown over Taiwan. Although Taiwan has some importance to the United States as a significant trading partner and sister democracy, its relevance to American economic and security interests hardly compares to Western Europe and Northeast Asia during the Cold War. Chinese officials recognize that.

At the same time, the island’s importance to China is much greater than Western Europe or Northeast Asia was to the Soviet Union. To Beijing, Taiwan is not merely a political and economic prize. The status of the island is caught up in issues of national pride and prestige.

Taiwan is a reminder of China’s long period of humiliation at the hands of outside powers. When such potent emotions are engaged, political leaders do not always act prudently. Nor is it certain that Chinese leaders will be as risk averse as the old Soviet hierarchy.

The response of high-ranking PRC military officers when Adm. Dennis Blair, the commander of U.S. forces in the Pacific, warned them a few months ago that the United States would come to Taiwan’s aid in the event of an unprovoked attack was not reassuring.

The military officers reportedly reacted with disbelief verging on scorn. It matters little if their skepticism is right or wrong. If they believe the U.S. commitment is a bluff, they might be inclined to call it.

Applying the lessons of the Cold War to deter China from coercing Taiwan is likely to lead to either a humiliating U.S. retreat or an armed conflict.

Selling weapons to Taiwan is a reasonable course of action. A militarily capable Taiwan makes it less likely that Beijing will contemplate using coercion to pursue its goal of reunification. But a U.S. security commitment is a very different matter.

Washington should couple its arms sales to Taiwan with a firm statement that the United States will not become involved in any armed struggle between Taiwan and the PRC.

Instead, Bush’s pledge to intervene to defend Taiwan increases the likelihood that the United States will someday end up in a catastrophic war with China.