Is America becoming more pro-life? A new poll by Gallup says so. The poll, released on the Friday before President Obama addressed Notre Dame University, thrilled the anti-abortion movement—and offered Republicans their first glimmer of hope in months.

But the poll is wrong. Worse, it’s misleading—and threatens to send Republicans careening in precisely the worst possible direction in pursuit of votes they will not find.

Charles Franklin of Pollster.com explains the poll’s big technical error. Gallup oversampled Republicans. At a time when only 1 in 5 Americans identifies as Republican, 32 percent of the respondents in Gallup’s survey group identified themselves as Republican. Franklin offers some interesting explanations of how this oversampling could have occurred. But what matters most are the consequences.

As the Republican Party shrinks, it becomes more conservative. Today’s shriveled GOP is much more pro-life than the robust GOP of years past. So if you oversample Republicans, you are oversampling pro-lifers. Sure enough, when you look at Gallup’s breakdown of its results, all the rise in anti-abortion feeling is concentrated among self-identified Republicans.

To paraphrase Norma Desmond in “Sunset Boulevard”: The pro-life movement isn’t bigger—it is the Republican Party that has gotten smaller.

Beyond the technicalities, Gallup’s poll is wrong in a far more important way. For all their vehement disagreement, pro-lifers and pro-choicers agree that the abortion debate is about rights: the woman’s right to choose, the unborn child’s right to life. Pro-choicers may sternly disapprove of the irresponsible woman who casually discards one pregnancy after another. Pro-lifers may feel tremendous sympathy for the woman considering abortion because she feels she cannot raise a child on her own. Both agree that the reason for the abortion is absolutely irrelevant.

Yet almost every survey suggests that the considerations rejected by strong partisans as irrelevant are the considerations that matter most to the voting majority, who reject both the pro-life and the pro-choice cause. Gallup’s 2008 annual survey of the issue and its much-criticized 2009 survey agreed on one point: The proportion of Americans who answer that abortion should either be legal in all circumstances or illegal in all circumstances has held steady at 45 percent. (The Quinnipiac poll more plausibly assesses the two most certain groups at just 29 percent of voters.) The majority of Americans think it should be legal under some circumstances, but not under others.

Even these numbers understate the muddiness of the public position. At the peak of the controversy over partial birth abortion, polls found that more than 60 percent of Americans wanted it banned. Clear? Yes—until you asked about the health of the mother. Then 60 percent wanted it legal.

For reasons best known to themselves, pollsters rarely pose the question in the way that Americans themselves talk about it.

“Suppose a woman has two boyfriends at the same time, gets pregnant, and wants an abortion so she won’t have to admit to her two-timing. Is that okay?”

“Now suppose another woman is working her way through college. Her boyfriend dumps her when she tells him she’s pregnant. If she carries the baby, she’ll have to drop out and take any job she can find in this tough economy. She has decided abortion is her best choice—should the government stop her?”

Logically, legally, philosophically such an approach represents an incoherent mess. And yet … that’s probably where most people are on the issue. Which may also explain why so many people respond so well to those, like President Obama at Notre Dame, who gracefully attempt to reconcile the irreconcilable.

This leads to the special danger the (mis)information in the Gallup poll presents to Republicans. As multiple polls show, Republican appeal has drooped to levels not seen since the aftermath of Watergate, maybe not since the 1930s. Those Republicans who remain committed to the party are, as the abortion poll suggests, the most conservative—especially the most socially conservative. Very understandably, they wish to believe that the party can recover by focusing most on people like themselves. (It takes very little evidence to persuade people to do what they want to do anyway.)

Yet a strategy that emphasizes abortion and other family life issues can only lead Republicans to greater difficulty. The pro-life segment of American opinion is disproportionately black and Hispanic. (Hispanics are almost 10 points more pro-life than whites.) Unfortunately, as repeated disappointment should by now have taught Republicans, abortion is just not a voting issue for these voters. They vote for their pocketbooks, as poorer people of all races usually do.

The votes available for Republicans to recoup are those of more highly educated and more affluent whites who have been lost since 1998, and especially since 2006. Among these voters, especially the women, abortion is the very opposite of a vote-getter.

Gallup has again dangled in front of Republican decision-makers the false promise of a multi-ethnic, socially conservative voting majority that can be deployed to elect economically conservative Republicans. Yet in reality, socially conservative, lower-income nonwhites put their economic interests first and vote Democratic—while economically conservative affluent whites put their cultural votes first and also vote Democratic! It’s the worst of all possible worlds.

The road to Republican recovery begins by reconstituting the voting base we used to have. The Republican Party should remain pro-life, yes, but more quietly and inclusively so. We must emphasize that non-pro-lifers can have a place at our table too. (One way to demonstrate that would be to combine a non-pro-life running mate with a pro-life presidential candidate in 2012.)

And one more thing: When reading polls, read them all the way to the bottom. See that line about accuracy “19 times out of 20”? Whenever you see anything that seems too good to be true, you need to ask: Could this be that 20th time?