WASHINGTON — Every four years, defenders of abortion rights proclaim that the fate of Roe vs. Wade hangs on the outcome of the presidential election.
This year, they may be right.
Through most of the 1990s and until recently, the Supreme Court had a solid 6-3 majority in favor of upholding the right of a woman to choose abortion. But the margin has shrunk to one, now that Justice Sandra Day O'Connor is retired and has been replaced by Justice Samuel A. Alito Jr.
And Justice John Paul Stevens, a leader of the narrow majority for abortion rights, is 88.
"Clearly, Roe is on the line this time," said Indiana University law professor Dawn Johnsen, a former lawyer for NARAL Pro-Choice America. "It is quite clear they have four votes against it. If the next president appoints one more, the odds are it will be overruled."
Some advocates worry that the perennial cries of "Roe is falling" has had the effect of muting such claims.
"What we find scary is that people don't understand what's at stake," said Kathryn Kolbert, president of People for the American Way. "In the next four years, one to as many as three Supreme Court justices may step down, and they all will come from the liberal end of the court."
But that doesn't mean abortion or the fate of the Roe decision is a rallying cry on the campaign trail for either Democrats or Republicans. The two parties have staked out opposite positions, but their candidates rarely mention them when campaigning.
The abortion issue is enormously important to the base of both parties, political strategists say, but it is a touchy and difficult matter to raise with an audience of swing voters and those who are undecided.
"People are conflicted about it," said Peter Fenn, a veteran Democratic strategist. "If you are campaigning in Scranton, you want to make the lunch-bucket argument. When the economy is driving the race, you don't want to ignite the culture wars."
On the Republican side, Kenneth L. Khachigian, a California attorney and a campaign advisor to President Reagan, said abortion had become a key issue in the primary races but not in the general election.
"It is a motivating factor at the grass-roots level," he said.
When Republican John McCain was considering his choices for a running mate, conservative activists threatened a rebellion at the GOP convention in St. Paul, Minn., if he were to choose a supporter of abortion rights.
Instead, McCain galvanized his support with conservative activists when he chose Alaska Gov. Sarah Palin, who opposes abortion even in cases of rape and incest.
McCain's website says he "believes Roe v. Wade is a flawed decision that must be overturned."
But having established his opposition to abortion, McCain has no reason to campaign on the issue, Khachigian said. "At this stage, when you focus on the 10% who are out there and have not decided, you can figure they are not going to decide based on your view of abortion or Roe vs. Wade," he said.
Democrat Barack Obama has called himself a strong supporter of abortion rights.
"A woman's ability to decide how many children to have and when, without interference from the government, is one of the most fundamental rights we possess," he told NARAL Pro-Choice America. "I believe we must work together to reduce the number of unintended pregnancies," he said.
But Obama, like McCain, does not talk up the issue on the campaign trail.
Polls show the American public remains closely split on abortion. Most say they favor legal abortion, with some restrictions. In August, a poll for the Pew Research Center for the People & the Press found that 54% said abortion should be generally legal, and 41% said it should be mostly illegal.
This week, the Supreme Court opens its term, and abortion is not on the docket there, either. The justices have generally steered away from abortion-related disputes in recent years. They remain closely and bitterly divided on the issue.
Four justices -- Ruth Bader Ginsburg, David H. Souter, Stephen G. Breyer and Stevens -- have consistently supported the right to abortion, and they have voted to strike down restrictions.
Justices Antonin Scalia and Clarence Thomas have said the Roe decision should be overturned, leaving the states or Congress to decide the abortion issue.
Chief Justice John G. Roberts Jr. and Alito served as young lawyers in the Reagan administration, which was committed to reversing Roe. And since joining the court, they voted to uphold the federal Partial-Birth Abortion Ban Act.
In the middle, Justice Anthony M. Kennedy has supported strict regulation of abortion, but he has opposed a ban.
If Stevens or Ginsburg were to be replaced by a staunch conservative, that would tip the majority against abortion rights. However, it is not certain that Roberts and Alito would join Scalia and Thomas in pressing to overrule the right entirely.