By Clare Murphy
BBC News Online
The foes and champions of abortion rights, traditionally one of America's most polarising issues, are gearing up for a battle which could spill over into next year's presidential election.
At stake, both sides believe, is the future of Roe v Wade, the 1973 Supreme Court ruling which has enabled American women to terminate pregnancies safely and legally.
We are waiting for Mr Bush to live up to his promises on the right to life
Former adviser to President Reagan
The issue has moved to the foreground amid rampant speculation that up to two of the nine judges who sit on the country's most powerful court may resign.
This would clear the way for President George W Bush, an opponent of abortion, to seek new, life-long appointments who would be willing to clamp down on a woman's right to choose.
In the balance
The Supreme Court is currently split narrowly in favour of Roe v Wade.
Chief Justice William Rehnquist, a 78-year-old with a bad back who is one of the opponents of the ruling, is the most likely to decide that now is the time to retire from the bench.
His replacement by another conservative judge would clearly not tip the balance.
But if Sandra Day O'Connor, a 73-year-old Supreme Court justice who has been the key swing vote on reproductive issues decided it was time for her to go too, that could be significant.
The resignation of Justice O'Connor could shift the balance
Despite being appointed by a Republican president, she supports abortion rights. A replacement selected by President Bush may not.
Although the prospect of their retirement is as yet a purely speculative issue, it is likely that conservative judges thinking about stepping down would do so under a Republican president in the hope of seeing their seats filled by the like-minded.
At least one Democrat senator who wants to run for president next year, John Kerry, says he will block any Supreme Court nominee who opposes the legality of abortion, indicating that the issue would become a key feature of his election campaign if he wins the nomination.
"I am prepared to filibuster, if necessary, any Supreme Court nominee who would turn back the clock on a woman's right to choose," he said.
"Just one more anti-choice justice could get rid of the protections of Roe."
Mr Bush's senators could overrule any such move by Mr Kerry and his colleagues, but this would be an extremely controversial step to take.
Roe v Wade is under threat
US Rep Carolyn Kilpatrick
Alternatively, Mr Bush could choose a more moderate candidate to join the Supreme Court, but he runs the serious risk of alienating core conservative voters who have eagerly awaited this opportunity.
"If Mr Bush doesn't make the most of any vacancy, and he ignores the grassroots who want an end to abortion, this will have an impact on next year's election," says Gary Bauer, once domestic policy adviser to President Reagan and now the head of a right-wing lobby group, American Values.
"We are waiting for him to live up to his promises on the right to life. If he doesn't, people may not come out to vote next year, and in a closely fought election that will be significant," he told BBC News Online.
The discussion about the Supreme Court comes at a time when American public opinion seems to be shifting on the merits of the right to choose.
Congress has recently banned a controversial form of late abortion, the first legislative restriction on a woman's right to choose since Roe v Wade.
While many doctors acknowledged that the partial-birth procedure was an unpleasant one, they noted that it was necessary in a handful of cases each year.
The murder of pregnant Laci Peterson has inadvertently given anti-abortionists a new weapon
Anti-abortionists have also been pressing for Congress to approve a bill that would consider the foetus an individual in case of violent crimes against pregnant women, legislation that could have a serious impact on abortion rights.
Their case has gained ground amid public outrage over the brutal murder of a young Californian, whose dead body was found washed up on a beach earlier this year, with that of her unborn baby next to her.
President Bush has given the bill his blessing.
"These cases have certainly helped our cause," says Carol Tobias, a spokeswoman for the National Right to Life campaign.
"The partial birth issue in particular has given people a real insight into the nature of abortion, and the public is definitely leaning more our way."
Indeed, a recent survey gives anti-abortionists even greater grounds for hope.
A poll for the Center for the Advancement of Women suggested that preserving abortion rights is not a priority for the majority of American women.
Only 30% of those surveyed believe abortion should be generally available, and over 50% said it should only be available in cases of rape, incest, or when the mother's life was at risk.
Security concerns are women's top priority, with domestic violence and assault appearing as their primary concern in the survey.
"You cannot underestimate how 11 September has changed the way people view the world and altered their priorities," Democrat congresswoman Carol Kilpatrick told BBC News Online. "Security and risk are major issues now, and abortion rights just don't really figure that high in people's concerns."
"I believe that most Americans are at heart pro-choice but Democrats do need to start rallying people behind these rights - Roe v Wade is definitely under threat."
But whether all the Democrat contenders will choose to throw their weight behind the issue as Senator John Kerry intends to do remains to be seen.
If the right to abortion is so far down the list of voters' priorities, some may feel Roe v Wade is not worth the effort in the battle to deny the Republican president a second term.