A NATIONAL SHIFT ON ABORTION?…. The new Gallup poll on public attitudes on abortion rights offers some unexpected results.

A new Gallup Poll, conducted May 7-10, finds 51% of Americans calling themselves “pro-life” on the issue of abortion and 42% “pro-choice.” This is the first time a majority of U.S. adults have identified themselves as pro-life since Gallup began asking this question in 1995.

This seems to point to a striking reversal. A year ago, 50% self-identified as “pro-choice,” and 44% were “pro-life.” The new poll shows a complete turnaround, with pro-choicers dropping eight points, and pro-lifers climbing seven points. It’s the first time since Gallup started polling on the question that “pro-life” garnered a majority.

So, what’s happened? It’s certainly possible that nothing happened and the poll is simply an outlier. There’s no obvious reason to explain this kind of dramatic shift over the course of just one year, and there are other recent polls — including one with a larger sample — that show different results. Once in a while, when poll results seem wrong, it’s because they are wrong.

What’s more, the same Gallup poll asked respondents, “Do you think abortions should be legal under any circumstances, legal only under certain circumstances, or illegal in all circumstances?” Here, a majority (53%) wants to see abortion legal under certain circumstances, while the other groups of respondents were evenly split.

Of course, since “certain circumstances” is frustratingly vague, this only tells us that the majority of Americans reject the notion that life begins at conception, but they’re comfortable with some state-imposed restrictions on reproductive rights. What kind of restrictions? We’d need a more detailed poll to say with any confidence.

I suspect, though, that polls like this are asking the wrong questions. These are the questions that seem to have the most policy salience in the debate:

* Some lawmakers and activists would like to see a constitutional amendment prohibiting abortions in the United States. Do you support or oppose such an amendment?

* The Supreme Court ruled in Roe v. Wade that women have a right to an abortion. Do you think the Supreme Court should overturn Roe?

It’s interesting to know how many Americans consider themselves “pro-choice” and “pro-life,” but there are plenty of folks for whom these labels are ambiguous. Some, for example, might say they’re “pro-life,” but don’t want to see the government mandate their beliefs on everyone else. I’m more interested in the two questions I pose, because they’re more likely to have a political effect.

Nevertheless, the right is excited about the recent developments. The Gallup poll comes on the heels of a Pew survey that also shows support for abortion rights falling.

All things being equal, I think Dana Goldstein’s take is the right one: “[E]ndless coverage of rare, late-term abortion — combined with complacency due to abortion’s long-term legality — has made many Americans ‘squishy’ on the issue, open to various restrictions while still supportive of general access to the procedure…. In general, I think we should be wary of reading too much into two polls. Longer-term trend lines confirm that we are living in a country divided on abortion but with a clear preference for choice in most circumstances.”

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.