On the "war on terror," no Republican contender but John McCain equals Giuliani in longtime efforts on behalf of that war or in understanding and articulating the threat radical Islam poses to America and to liberty on earth. And they both have great courage. If the only issue that mattered in the next election were the "war on terror," all those -- including Democrats and independents -- who share this awareness of the Islamist threat could be happy with either candidate.

Anyone who does not understand the nature of the war that liberty is now waging against tyranny should not be president of the United States. And the Democratic candidates until now have shown no such understanding -- the term "Islamic terror," invoked by nearly every Republican candidate, was not mentioned once in any of the Democrats' debates. But while this understanding is necessary, it is not sufficient. America needs a strong leader domestically, as well as internationally.

And when it comes to being strong on both domestic and international issues, it seems that no presently viable Republican candidate matches Rudy Giuliani.

The current leading contender, Sen. John McCain, is a great American and a true American hero. However -- and this is written in sadness -- on too many significant issues, conservatives, and even many moderates, would not only disagree with John McCain but also would question his judgment.

John McCain is a leader in promoting legislation on behalf of "campaign finance reform." Aside from limiting freedom of speech, such legislation has done real damage to our democracy. For example, it has severely limited how much money one American can give to another American to run for public office. Consequently, increasingly only the very famous and/or the extremely wealthy -- e.g., California Gov. Arnold Schwarzenegger, former senator -- now governor -- Jon Corzine of New Jersey, and New York Mayor Michael Bloomberg can run for office. The percentage of very wealthy members of the U.S. Senate is the greatest in American history. Thanks to John McCain and "campaign finance reform," Americans running for public office can spend hundreds of millions of dollars on themselves, but individuals can give only $4,000 to non-wealthy candidates.

John McCain, in a recent Republican debate, asked, "Why shouldn't we be able to re-import drugs from Canada?" (With its socialized medicine, Canada buys drugs at cheaper rates.) This is not merely not conservative; it is radical and it is foolish.

As George Will wrote this week, "That amounts to importing Canada's price controls, a large step toward a system in which … new pain-relieving, life-extending pharmaceuticals would be unavailable. … When Mitt Romney interjected, 'Don't turn the pharmaceutical companies into the big bad guys,' McCain replied, 'Well, they are.' There is a place in American politics for moralizers who think in such Manichaean simplicities," Will concludes. "That place is in the Democratic Party."

John McCain twice voted against President Bush's tax cuts.

John McCain has wholly bought the politically correct view of man-made carbon emissions leading to global catastrophe. It is true that all the Republican candidates pay lip service to a hysteria that is capable of truly harming the American and world economies, but John McCain is the major Republican activist on this issue. He is co-author, with Sen. Joe Lieberman, of a bill empowering Congress to legislate carbon emissions, and he has dismissed all scientific questions with Al Gore's, "The debate has ended."

John McCain's view of drilling for oil in a remote corner of Alaska: "As far as ANWR is concerned, I don't want to drill in the Grand Canyon, and I don't want to drill in the Everglades." Any comparison of a part of frozen Alaska that has been seen by almost no human being in history with the Grand Canyon and the Everglades, which tens of millions of people have visited and always will visit, is, shall we say, odd.

John McCain is a good man, a good American and a good leader, but he is not a conservative in some important ways. That is why John Kerry considered John McCain as a possible running mate. Would John McCain be a better president than a Democrat? Yes, primarily because of his stance on the "war on terror." But conservative supporters of McCain need to acknowledge that some fundamental conservative principles -- as noted above -- probably would be rejected in a McCain presidency.

Rudy Giuliani may have made a great mistake by not campaigning in New Hampshire, Nevada, Iowa and South Carolina. But between Rudy Giuliani (and, for that matter, Mitt Romney) on the one hand and John McCain on the other, there is little question as to who more embodies mainstream conservative and Republican principles.

But Giuliani is not merely more of a conservative than John McCain. In fact, if it is Ronald Reagan that Republicans want, Giuliani is extraordinarily close to that venerated man. Ronald Reagan stood for two great beliefs: that big government is a big problem for a free society and that America must be militarily strong and lead the war against global communism.

Substitute "global jihadism" for "global communism" and you have Rudy Giuliani's twin pillars. His one major weakness in appealing to all conservatives is that he is for abortion rights. Let me, then, briefly address all those who, like me, consider nearly all abortions immoral.

Ronald Reagan was pro-life, and it mattered little to the pro-life cause. Concerning abortion, what matters most in a president is the type of judges he appoints to the Supreme Court. As George Will wrote on behalf of Giuliani, "The way to change abortion law is to change courts by means of judicial nominations of the sort Giuliani promises to make." It is extremely unlikely that John McCain would appoint similarly conservative judges. After all, why would he appoint judges like Scalia and Alito who apparently differ with him on the constitutionality of McCain's own "campaign finance reform" laws?

Pro-life Republicans need to ask themselves: Will a Democrat or Giuliani as president render abortion less common in America? The best is the enemy of the better. And Giuliani is far better on abortion than any Democratic nominee.

Giuliani is for school vouchers, against bilingual education, for reducing taxes further, for reducing government spending. And he has well-thought-out positions on how to achieve these things. He also has the experience of cleaning up the most liberal major city in America.

I write this column aware that Giuliani may have lost his chance at getting the Republican nomination. But I could not live with my conscience if I did not articulate one week before the potentially decisive Florida primary my beliefs about Rudy Giuliani.