Protesters from both sides of a critical issue stormed Capitol Hill yesterday, forcing pedestrians off sidewalks to make their voices heard. Yesterday, the 35th anniversary of Roe v. Wade, the issue of abortion rights once again took center stage.

Three and a half decades later, as Republican presidential candidates fight for the label of most pro-life and accuse each other of infidelity to the cause, activists on both sides hope desperately for the issue to play a role in the general election. Their side, they both believe, will win the day, and a pro-choice or pro-life platform will make the difference between a win and a loss. But in a general election, does abortion, in fact, move votes? The answer, according to polls and to recent history, is probably not.

Virtually every poll that tests the question finds a small majority -- in the area of 55% -- say abortion should be legal in all or most cases. Around 45% say it should be illegal in most or all cases. That number rarely strays more than a point or two. Meanwhile, asked what issue would be a deal-breaker if a voter disagreed with a candidate, just 8% said abortion, according to a Fox News poll conducted in mid-November. In the same poll, 24% said the war in Iraq would be a deal-breaker, while 10% said health care and 10% said economic policies or taxes (immigration scored even lower than abortion, at 5%).

It is hard to think of a contest in recent years that has been decided largely on pro-choice or pro-life platforms. While those positions are crucial to some Republican primary contests -- just ask Mitt Romney and Rudy Giuliani -- the issue has only played a small role in the Democratic debate: Hillary Clinton has pointed out that some of Barack Obama's infamous "present" votes occurred on abortion issues, but other than that, every candidate is assumed to be pro-choice. On the GOP side, top life advocates are split between a number of candidates, including Giuliani (Pat Robertson), Romney (Paul Weyrich and James Bopp Jr.) and John McCain (Sam Brownback), not to mention countless backers of Mike Huckabee.

In fact, there is not a unanimous opinion among the Republican electorate about the issue. Exit polls from South Carolina showed more than a quarter of GOP voters thought abortion should be legal in all or most cases. Those positions did not stop them from casting a vote for candidates quite outside their thinking: 20% of those who said they thought abortion should be legal in all cases voted for Huckabee, who doesn't have a pro-life bone in his body, and 74% voted for McCain, Romney or the recently departed Fred Thompson, none of whom can be called pro-choice. More than half those voting in the New Hampshire GOP primary said abortion should be legal in all or most cases.

An LA Times/Bloomberg poll in late November showed that just 28% of Republicans would be less likely to vote for Giuliani, despite his pro-choice stand, while 15% said they would be more likely to vote for him given that stand. To more than half of Republicans, Giuliani's position, anathema to what is supposed to be a huge issue to the GOP, would not make a difference.

That abortion is becoming less of a vote-moving issue does not mean its importance is diminished by any means. Interest groups and activists on both sides are as passionate about it as any other issue, and for good reason: It is one of the first political issues on which anyone forms an opinion, and few are swayed. Groups like EMILY's List, NARAL, and National Right-To-Life maintain strong positions in the Democratic and Republican Parties, both primary vote-winners and as money machines.

But, as an issue to appeal to moderate voters, abortion -- either the pro-choice or pro-life sides -- will not win an election. It seems to be more of a cultural issue than a political issue, and while battles over Supreme Court nominees will be intense, the debate in a general election will remain circumspect. Candidates will talk about the types of judges they would nominate to the Court, but, as polls show, overt appeals to pro-life or pro-choice voters do little more than motivate a base.