That's what a new Pew study finds: after demonstrating solid support for legal abortions a year ago, Americans are now essentially split on the question.

Asked whether abortion should be legal or illegal "in all or most cases," the country favored abortion rights 54-41 in August 2008; now, opposition has gained ground, as Americans still want abortion to be legal, but only by a margin of 47-45.

According to Pew's chart, Americans were last split on abortion near the beginning of President Bush's first term:

abortion poll.gif

This isn't the first sign of anti-abortion momentum we've seen this year: in May, Gallup reported that more Americans identified themselves as "pro-life" than as "pro-choice," though that survey also found a slight shift to the left among people who thought abortion should be legal under "most" or "only in a few" circumstances.

Social issues have seen some leftward movement in the past year, as gay marriage in particular has caught on in several states.

Pew detects a pattern in the abortion numbers: it's Republicans who are shifting. And that goes to support Pew's explanation that it may be an Obama effect:

No single reason for the shift in opinions is apparent, but the pattern of changes suggests that the election of a pro-choice Democrat for president may be a contributing factor. Among Republicans, there has been a seven point decline in support for legal abortion and a corresponding six point increase in opposition to abortion. But the change is smaller among Democrats, whose support for legal abortion is down four points with no corresponding increase in pro-life opinion. Indeed, three groups of President Obama's strongest supporters - African Americans, young people and those unaffiliated with a religion - have not changed their views on abortion at all. At the same time, fully half of conservative Republicans (52%) - the political group most opposed to abortion - say they worry Obama will go too far in supporting abortion rights.

Now that there's a pro-choice president, liberals aren't as worried about abortion: makes sense. And, as conservative energy swells against the president in a not-so-directed manner--some protest bailouts, some protest health care, some protest government debt--the opposition has hardened against the new leader. That seems to make sense too.

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