In the campaign for the Republican presidential nomination in 2000, Sen. John McCain, R-Ariz., waged a long, spectacular battle against Gov. George W. Bush of Texas. In the process, McCain made himself the hero of many independents and moderate Republicans -- and not a few Democrats -- by dissenting from conservative dogma on a variety of important issues. After winning several of the early primaries, however (with the help, where they could vote, of those independents and Democrats), he was defeated soundly by Bush in South Carolina, in large part because he had denounced the Rev. Jerry Falwell, founder of the Moral Majority and a leader of the social conservatives, as "polarizing" and an agent of "intolerance." Bush went on to win the nomination, but McCain had earned the lasting devotion of America's liberal media.

Thereafter, McCain continued to disagree strongly with Bush on certain aspects of the president's program, most notably the 2001 tax cuts. (McCain was one of only two Senate Republicans who voted against them.) On the other hand, he has steadfastly backed the war in Iraq while support for it has eroded in the public at large, and has proposed (with Sen. Ted Kennedy) a compromise bill on illegal immigration that is much closer to Bush's ideas on the subject than to the desires of the conservative base.

Truth to tell, it has long been difficult to decide whether McCain is fundamentally conservative or simply an unpredictable maverick whose views on important subjects are impossible to anticipate. That is why, despite public opinion polls indicating that he could mop up the floor with Hillary Clinton in the presidential election of 2008, it has seemed likely that the conservatives who will dominate the 2008 Republican convention would deny him the nomination.

Now, however, observers have noted what appear to be significant changes in some of McCain's signature policies. He has voted to make permanent the Bush tax cuts he once opposed so stubbornly. He has accepted an invitation to address the forthcoming commencement at Falwell's Liberty University. Having said in 2000, "I would not support repeal of Roe v. Wade," he told CBS last January (when asked whether the Supreme Court may someday ban abortions), "I've never agreed with Roe v. Wade, so it wouldn't bother me any."

Is McCain flip-flopping? Of course he is. He is running, hard, for the presidency (though he says he will decide about that later), and he is taking the steps that are absolutely essential if he is to win the Republican nomination. But he is far from the first politician to have done so, and accusations of hypocrisy are a bit unfair. He has always had an independent streak, which is a key aspect of his personality. (As a prisoner of war in Vietnam, he refused early release as the son of an admiral.) Given his family's military background, his basic views are almost certainly conservative. Of course, how they might manifest themselves in the White House is problematic, and it may be relevant to note that he also has a famous temper.

To be sure, his current swing to the right on many issues may disenchant the liberal media and many of the independents and Democrats who have hitherto been among his strongest supporters. And it may not even convince the Republican conservatives he has so often disappointed, and whose support is essential to his nomination.

In addition, he faces a serious competitor in Massachusetts Gov. Mitt Romney, who is enormously attractive on television and carries far less baggage than McCain in terms of liberal opinions. And if Romney's Mormonism proves more than the GOP's evangelical Christians can stomach, Virginia Sen. George Allen stands ready to offer an alternative whose 2004 rating by the American Conservative Union was 92 out of a possible 100.

But right now, by lining up squarely on the conservative side of so many issues, John McCain is making himself an even more formidable candidate for his party's nomination.