For decades, the Republican Party has subjected its presidential candidates to an abortion "litmus test." Now one of its presidential candidates is subjecting the Republican Party to a new kind of abortion litmus test.

The party's reaction to Rudy Giuliani is a test of its priorities. What do Republicans care about more: winning the War on Terrorism, or achieving the agenda of the religious right?

Such questions always come to the forefront in a party's primaries. Because relatively few people vote in the primaries, these contests are always dominated by a party's most politically active, most passionate supporters. So the question of the primaries is: what issue are Republicans most passionate about? If they are passionate about fighting radical Islam, Giuliani has positioned himself as the leading candidate. If they are more passionate about banning abortion, then we should see a surge of support for a candidate who is strongly committed to the agenda of the religious right -- someone like Kansas Sen. Sam Brownback or maybe former Arkansas Gov. Mike Huckabee.

Tuesday's night's debate gave us an idea of how the candidates are grappling with this issue. It also confirmed that the Republicans' test on this issue will be a major, recurring theme of the campaign.

The most interesting reflection of the way Republicans are reacting to Giuliani is the fact that, despite numerous questions grilling him on his position on abortion, there is only one Giuliani moment that most people remember: the moment when he broke the format of the debate to challenge Texas Rep. Ron Paul for blaming September 11 on America.

Demonstrating why Ayn Rand was right to dismiss Libertarians as "hippies of the right," Representative Paul picked up the basic anti-war argument of the far left. The terrorists, he said, "attack us because we've been over there; we've been bombing Iraq for 10 years.... We need to look at what we do from the perspective of what would happen if somebody else did it to us."

Giuliani fixed Paul with a withering look and replied: "That's really an extraordinary statement. That's an extraordinary statement, as someone who lived through the attack of September 11, that we invited the attack because we were attacking Iraq. I don't think I've heard that before, and I've heard some pretty absurd explanations for September 11th. And I would ask the congressman to withdraw that comment and tell us that he didn't really mean that."

This moment won the biggest applause of the night, and it was the moment most repeated on the evening news.

But the general attitude of the Republican Party was stated most clearly Tuesday night by Arizona Sen. John McCain: "What this is really all about is: who's most prepared to lead in this ... central challenge that we face called radical Islamic extremism?"

That's the central issue, and abortion has been treated, so far at least, as a subordinate issue.

But that doesn't mean this is going to be an easy choice for Republicans to make. The choice between putting the war first and putting abortion first exposes a basic ideological contradiction within the Republican coalition. Republicans are supposed to stand for the defense of freedom abroad and for greater freedom at home -- except which it comes to the moral crusades of the religious right.

This contradiction was revealed in an exchange between Giuliani and Huckabee. Explaining his support for a woman's right to choose an abortion, Giuliani expressed it in terms of the pro-freedom half of the Republican ideological coalition:

"There are people, millions and millions of Americans, who are as of good conscience as we are, who make a different choice about abortion. And I think in a country where you want to keep government out of people's lives, or government out of people's lives from the point of view of coercion, you have to respect that. There are things that you can oppose, things you can be against; and then you can come to the conclusion, in the kind of democracy we have, the kind of society that we have...where we want to keep government out of people's personal lives, that you can respect other people's view on this," he said.

There you have it: if Republicans want to keep government coercion out of people's lives, then they have to respect a woman's right to choose.

For his part, Huckabee replied: "Now, if something is morally wrong, let's oppose it. The honest argument is, 'I don't think it's morally wrong,' and someone could take that position and then justify abortion. But if it's wrong, then we ought to be opposed to it."

There's the opposite position: if something is morally wrong, we must oppose it--through the use of government coercion. Does this mean that government should outlaw everything that these moralist find to be reprehensible? And where are the limits of this moral policework? Consider the way, for example, that Sam Brownback expanded on the "pro-life" agenda in Tuesday night's debate: "We ought to protect [life] in all circumstances in all places, here in the womb, somebody that's struggling in poverty, a family that's struggling. We should work and look at all life, be pro-life and whole-life for everybody."

"Pro-life and whole-life" sounds a lot like "cradle to grave" government paternalism. Logically, shouldn't these Republicans be joining forces with John Edwards instead of ridiculing his high-priced haircut?

The agenda of the religious right--the desire to use government coercion to outlaw that which evangelical moralists find to be wrong--has always clashed with the pro-freedom, pro-free market agenda for which most Republicans also declare their support. But the clash is particularly glaring in dealing with our current enemy in the War on Terrorism. Former Massachusetts Gov. Mitt Romney did a decent job of defining the nature of that enemy:

"It is critical for us to remember that Iraq has to be considered in the context of what's happening in the Middle East and throughout the world. There is a global jihadist effort. Violent, radical jihadists want to replace all the governments of the moderate Islamic states, replace them with a caliphate. And to do that, they also want to bring down the West, in particular us."

The "caliphate" is a totalitarian Islamic dictatorship, one devoted to imposing Muslim religious values by force. That is the essence of our enemy, the essence of the evil we are fighting.

I'm not among those who get hysterical about the prospect of Republicans imposing a Christian "theocracy" in America -- but I do see a contradiction in fighting against totalitarian Islam abroad while endorsing religiously inspired government controls at home.

The good news is that Republicans so far have kept their priorities straight. So far, they seem to care more about the War on Terrorism than about abortion. How do I know that? Well, because that's what most of them are saying, in so many words.

Sure there are some mitigating reasons why anti-abortion Republicans might accept Giuliani, such as his promise to appoint "strict constructionist" judges in the vein of the current Supreme Court majority, which just approved the ban on "partial-birth" abortions. But that would be a pretty slim reed to save a candidacy, if abortion were the Republicans' top priority.

No, there is only one explanation for the fact that Giuliani is doing so well. The prevailing attitude was summed up recently by anti-abortion conservative columnist Jack Kelly when he backed Giuliani with this simple explanation. "I'll be a single issue voter in 2008. If we don't win the War on Terror, nothing else will matter very much."