Editor's note: This article originally appeared in the December 31, 2012, print edition of National Review.

No presidential candidate has run a campaign as aggressively supportive of abortion as the one Barack Obama did this year. The fact that he won — and by a bigger margin than any Republican has managed in more than 20 years — suggests that the politics surrounding the issue has changed, to the disadvantage of pro-lifers.

Abortion has never been a top voting issue for most people. Among those people who do vote on abortion, however, pro-lifers have outnumbered pro-choicers. In 1988, ABC’s exit poll found that 33 percent of voters had considered abortion a “very important” issue in making their decision, and they favored George H. W. Bush over Michael Dukakis by a margin of 54 percent to 45 percent. The CBS exit poll that year found 7 percent of the voters saying that it was one of the issues that mattered most, and they had broken 65 percent to 33 percent for the pro-life Republican.

That pro-life advantage persisted in the exit polls of 1992, 1996, and 2000. In that last year, 14 percent of voters in the Los Angeles Times exit poll said abortion was a top issue, and they picked George W. Bush over Al Gore, 58 to 41 percent. The exit pollsters stopped asking the question after that election, but other polls have almost always found the same pattern. Gallup has concluded that the issue of abortion has won Republicans a net 2 percent of the total vote in every presidential election from 1996 until today, except for 2004, when it netted them 7 percent. The Polling Company, a conservative firm hired by the National Right to Life Committee (NRLC), found that 25 percent of voters in 2008 identified opposition to abortion as having affected their vote, compared with 9 percent who said support for legal abortion affected theirs.

The full text of this article is available by subscription to National Review.