Yesterday’s Supreme Court decision upholding the 2003 federal partial-birth abortion ban was welcome news for pro-lifers. As luck would have it, the Gonzales v. Carhart ruling also gives them a useful framework for thinking about their dilemma in the next presidential election.

Pro-life activists have yet to coalesce around a candidate for the 2008 Republican nomination. While all the top-tier aspirants have their flaws, the frontrunner, former New York Mayor Rudolph Giuliani, remains unapologetically pro-choice. In the recent past, he has even opposed a partial-birth abortion ban virtually identical to the legislation the Supreme Court just upheld.

Many pro-lifers had hoped to arrive at an understanding with Giuliani. Even if he was unwilling to completely change his position on abortion, like George H.W. Bush and Mitt Romney, perhaps he could still move to the right on the issue. Accordingly, Giuliani reversed himself on partial-birth abortion and federal funding. He issued a terse statement approving of Gonzales v. Carhart, calling it “the correct conclusion” and saying “I agree with it.” And Giuliani has pledged to appoint originalist judges like John Roberts and Samuel Alito, two George W. Bush picks who voted with the majority.

Yet in recent weeks, pro-life descriptions of Giuliani have gone from dealmaker to deal-breaker. Socially conservative syndicated columnist Maggie Gallagher went from considering Rudy to opposing him. His anti-abortion rivals have been gaining in a few recent polls.

Two controversies appear to have caused pro-life second thoughts. First were the comments in which Giuliani seemed to reaffirm his support for taxpayer funding of abortion. Then the Des Moines Register quoted him as saying, “Our party has to get beyond issues like that.” “That” being abortion.

The Giuliani camp later clarified both points. On taxpayer funding, he vowed to uphold the Hyde Amendment. The campaign also pointed out that, in context, Giuliani’s “issues like that” comment was merely big-tent boilerplate in response to a question from someone worried about abortion dividing the party. But both defenses are less convincing on examination.

Giuliani merely said he would obey the law concerning federal financing of abortion. But what if a Democratic Congress tries to repeal the Hyde Amendment or expand its exceptions beyond rape, incest, and when the mother’s life is at stake? And his Des Moines comments do seem to betray a certain mindset about the pro-lifers’ role in the Republican Party. The unabridged remarks suggest that, at the very least, the GOP’s platform position on abortion is negotiable in a way that its stances on taxes and terrorism are not.

Despite the calls to leave litmus tests behind, pro-life Rudy reluctance is justified. If nominated, Giuliani would be the most pro-choice Republican presidential candidate in history. Even Gerald Ford, an archetypal Republican for choice, backed a constitutional amendment overturning Roe v. Wade during the 1976 campaign. Barry Goldwater, who was nominated before abortion became a national issue and outspokenly pro-choice in retirement, backed the human life amendment in his final Senate race.

Giuliani has feted NARAL and Planned Parenthood. He has praised Margaret Sanger and repeatedly accused mainstream pro-lifers of wanting to put pregnant women in jail. His concessions to date have been minor and offered without enthusiasm.

Abortion opponents can ill afford to give up their leverage in the GOP. Their position has little support among the cultural elite; many in the Republican establishment would like nothing better than to “get beyond issues like that.” If pro-lifers support Giuliani because he “hates” abortion, it will be difficult for them to criticize “personally opposed” Democrats like John Kerry in the future. Their campaign to get bishops to withhold communion from pro-choice Catholic Democrats will seem partisan and hypocritical. And the whole movement may be seen as less serious and less influential.

Nor will mealy-mouthed promises about judges do. In the same interview where he talked about taxpayer-funded abortion, Giuliani allowed that upholding Roe on stare decisis grounds was compatible with originalism. Indeed, Republicans held Supreme Court majorities when Roe was handed down, when it was reaffirmed in Planned Parenthood v. Casey, and when it was expanded to cover partial-birth abortion in 2000’s Stenberg v. Carhart.

Gonzales v. Carhart applied Roe and Casey as precedent. It stopped short of reversing Stenberg. Clarence Thomas’s concurring opinion rejecting the Court’s abortion jurisprudence was joined by Antonin Scalia but not Roberts or Alito — who, like majority opinion author Anthony Kennedy, were appointed by a pro-life president.

But Gonzales opens up room for Giuliani to make a meaningful deal with pro-lifers if he is so inclined. Like Casey, it will expand the number of permissible state abortion restrictions without toppling Roe. Giuliani could agree to disagree with pro-lifers about what abortion policy should ultimately look like while backing their efforts to increase legal protection for the unborn in accordance with the latest ruling.

That means Giuliani should put teeth in his support for the Hyde Amendment by pledging to veto any attempts to weaken it. He should continue to oppose partial-birth abortion and favor additional state restrictions, to the point of having his Justice Department defend the latter in federal courts. He must stop misrepresenting pro-life views and stop pretending Roe is good constitutional law.

In short, he must become operationally pro-life to deserve pro-life support. Happily, all this requires is that Giuliani be sincere in his current overtures.

Pro-lifers will likely face pressure from their conservative coalition partners to avoid making such demands. Their fellow Republicans will worry about the war and taxes (as if there aren’t pro-life candidates running who take mainstream conservative positions on those issues as well) and fear hostile media coverage. Given Giuliani’s considerable talents and popularity, should he refuse the deal and force pro-lifers to oppose him, old GOP hands will even worry about defeat.

But if abortion foes settle for anything less, they must understand that they aren’t just risking one presidential election — or even just the right to life. They will be setting a precedent that could endanger their cause’s status as a live issue in national politics.

It’s their choice.