WAR POLITICS : Bush looks to McKinley.

Karl Rove, President George W. Bush's resident political genius, has long had a fascination with another Republican president, William McKinley. In his first election in 1896, McKinley defeated the legendary populist Democrat, William Jennings Bryan, and created a new Republican majority built on the rising industrial elite. Republicans won six of the next eight presidential elections. Rove likes the implications for Bush.

That was all very interesting before September 11. But Rove's McKinley metaphor has only become more relevant since. It can help us understand how new foreign-policy challenges necessarily alter domestic politics.

To go back to McKinley: Between his election in 1896 and his re-election in 1900, the Spanish-American War intervened, producing an easy American triumph that left the United States in possession of Cuba, the Philippines, and Puerto Rico. "As years go, the period from 1898 to 1900 was a short time," wrote the historian George Mowry, "but in the nation's world circumstance, it represented the difference between relatively carefree adolescence and the beginnings of the burdens of maturity."

But many Americans, including Bryan, opposed an imperial role for their nation and hated the idea of Washington governing millions of people in the Philippines from afar. Nominated again in 1900, Bryan ran on an anti-imperialist platform. If you think Democrats are defensive these days, consider this from an August 1900 Bryan speech: "Although the Democrats realized that the administration would necessarily gain a political advantage from the conduct of a war in which the very nature of the case must soon end in a complete victory, they vied with the Republicans in the support which they gave the president."

Sound familiar? Bryan, of course, argued that Democrats could support the president during the war while opposing his subsequent policies. That may come to sound familiar, too.

From Rove's point of view, it has to be heartening that McKinley beat Bryan by an even larger margin in the 1900 election, the one fought around foreign policy, than in 1896. But, as Rove would acknowledge, no metaphor is perfect. The obvious difference between then and now is brought home by Secretary of State John Hay's famous description of the Spanish-American conflict as "a splendid little war." Even if the war on terrorism had been limited to a quick victory in Afghanistan--and no subsequent nation-building problems--that description would never have applied.

Everything the administration says points not to one or two splendid victories, but to a long struggle, as Nicholas Lemann ably documented in a recent issue of the New Yorker. Bush offers an unapologetically expansive view of America's responsibility to rearrange the world by bringing down governments that support terror.

The war on terror has often been appropriately analogized to the cold war. But the new war, in fact, represents an even larger assertion of American power--a quantum leap in American engagement more akin to the one that occurred on McKinley's watch. The cold war, after all, had a very specific goal: to contain and, if possible, roll back the power of the Soviet Union. In the new struggle, the United States will find itself juggling many objectives (and enemies) at once.

Communism was an evil system built around a flawed idea. Terrorism is evil, too--the president is right to use the word--but it is a method, not an idea. That means that "antiterrorism" will always be a less coherent concept than "anticommunism."

This explains why the administration has been tied up in knots over how to respond to Palestinian terror against Israel. The administration's commitment to opposing terror everywhere conflicts with its interest in getting the Palestinians and Israelis to negotiate. The president and his diplomats are wary of taking too hard a line against the Palestinians because their basic objective is to push the Israeli-Palestinian struggle off to the side. Then they can get on with the business of winning allies for a war against Iraq.

But this begs the question: if what's happening in Israel isn't "terrorism," what is? Yet if our goal, correctly, is a two-state solution, how can the United States square its refusal to negotiate with terrorists with its desire to push Israelis and Palestinians toward that end?

Because the balancing act that his policy entails is so difficult, Bush has set himself a much harder challenge than McKinley did. That doesn't mean Bush's domestic political position is weaker. On the contrary, Democrats are even more tentative these days than William Jennings Bryan was.

But Bush is going much farther than McKinley ever did. He wants to reorder the world. Our political system is only beginning to absorb the implications of his ambition.