LAST WEEK'S polls showed Sen. John McCain at the head of the Republican field in New Hampshire, and his reputation as a foreign policy heavyweight surely helped put him there. Mr. McCain's TV ads highlight his heroic Vietnam record; veterans are his staple audience. During one Republican debate, Mr. McCain's fluency in citing Dean Acheson's interactions with President Truman made the nationwide front-runner, Gov. George Bush of Texas, look superficial and tongue-tied. But it is not just heroism or fluency that distinguishes Mr. McCain. The substance of his policy differs sharply from that of other serious candidates.

Mr. McCain is an internationalist, just like Mr. Bush and both the Democratic candidates. But his brand of internationalism is more unilateralist and hawkish; he is more forthright in celebrating American power. In a speech last week, he spoke in one breath of the "interests of the United States and the rights of man." A few days earlier he declared that "the best guarantee that the new century will expand and not reverse humanity's triumphs in this century is the promise of America's principled world leadership."

That broadly accurate judgment leads Mr. McCain to some bold views. He takes a tough line not only on China and Russia but also on European allies. The Europeans do not carry their fair share of the defense burden, Mr. McCain rightly emphasizes. Therefore, they should stop carping at America's status as the world's only superpower and get on with modernizing their armed forces.

Mr. McCain is especially tough about rogue states such as Iraq and North Korea. He wants not just to denounce them and impose sanctions on them; he wants, in some cases at least, to topple their regimes. He proposes, for example, to build up anti-Milosevic Serbs and the Iraqi opposition. He wants to support ex-Soviet states that feel threatened by the rise of Russian nationalism. He is not afraid to cause offense--either to the Russians, or to allies that resist U.S. efforts against dictators.

Mr. McCain's heroic past and strong patriotism make an attractive package. His refusal to be complacent about the threats posed by rogue states is welcome. But the candidate needs to face two questions. The first is budgetary: It is hard to accept Mr. McCain's implication that his muscular policies could be paid for merely by cutting pork-barrel spending. The second goes deeper. The policy of "rogue state roll back" must include both an acknowledgment of the difficulty of the challenge and a sense of what kind of regimes the rogues will be replaced by.

In his foreign policy speech earlier this month, Mr. McCain skirted this issue. He made no mention of democracy promotion as a foreign policy priority; indeed, he swiped at the Clinton administration's preoccupation with "new-age" adjuncts to the traditional security agenda. This is politically understandable: From Haiti to Russia to the Balkans, building democracy has proved extraordinarily hard. But that is not a reason to give up on it.

Ronald Reagan, whom Mr. McCain likes to invoke, famously fought rogues: He backed anti-Marxist guerrilla groups in Afghanistan, Angola and Nicaragua. During the Cold War, these interventions could be justified by the need to contain the Soviet threat; it mattered less whether they furthered democracy.

But things are now different. The U.S. objective in Kosovo is not so much to contain Serbia, and certainly not to replace Serb tyranny with an Albanian alternative. The objective is to defend America's democratic and humanitarian values, which in turn will promote stability. Democracy promotion lies at the heart of the case for intervention in the post-Cold War world. Until he acknowleges this, Mr. McCain's forthright recognition of the threats posed by rogue states will lack a crucial element.