Forty years after the U.S. Supreme Court made a landmark ruling guaranteeing abortion rights under the Constitution, the decision is increasingly contested by opponents seeking to restrict access.
The delicate question over whether a woman has the right to choose to terminate a pregnancy -- and thus, critics argue, end a life -- has long caused deep and bitter divisions in the very fabric of American society, including several deadly incidents.
In what has become a yearly ritual, tens of thousands of pro-life activists will mark the anniversary of the Jan 22, 1973 "Roe v. Wade" ruling by marching in front of the Supreme Court.
This year's March for Life will take place three days later, on Friday, due to festivities surrounding President Barack Obama's inauguration to a second term on Monday.
The pro-choice movement, advocating for abortion rights, will organize local meetings, diners and conferences to mark the anniversary.
Polls lay bare the stark divide between the pro-life and pro-choice camps.
A Pew poll showed that more than six out of 10 Americans would not like to see the high court overturn Roe v. Wade, against 29% who would like to see it struck down -- opinions that have not shifted much since surveys conducted 10 and 20 years ago.
The latest survey, released Wednesday, also found that 53% of respondents said abortion was "not that important compared to other issues," an increase from 48% in 2009 and 32% in 2006.
And the ratio of those seeing abortion as a "critical issue facing the country" dropped from 28% in 2006 to 15% in 2009 and 18% today.
But abortion remains a heated political topic that can trigger the rise -- or downfall -- of conservative politicians in particular.
A flurry of abortion-related laws have nonetheless been passed at the state level, usually advanced by the powerful pro-life lobby and fought by the pro-choicers.
In May, Gallup said there had never been so few pro-choice supporters -- at 41% (against 56% in 1995) -- while 50% said they were pro-life (compared to 33% 16 years ago).
The anti-abortion activists "realize they can't really change the Supreme Court decision. They are not going to get an amendment to the Constitution, so they have adopted an incremental approach, state by state," said James Kelly, professor emeritus of sociology at Fordham University.
The Guttmacher Institute on sexual and reproductive health counted a record number of 92 abortion-related laws passed in 2011, and 43 in 2012.
They range across a wide spectrum, from measures limiting late-stage abortions to barring health care insurance reimbursements for the operation and a requirement for the pregnant woman to get a sonogram.
These legal restrictions "are different paths to the same goal, a goal of preventing a woman from being able to actually get an abortion, even if it's technically legal," said Jennifer Dalven of the American Civil Liberties Union rights group.
Others demand that centers providing elective abortion services comply with hospital norms that namely regulate door widths and available parking spots.
"The sole purpose is not to make people safer; the sole purpose is to close the clinics," said Jon O'Brien, president of Catholics For Choice.
About 1,800 clinics provide abortion services today across the United States, but 83% of counties do not have such centers. There is only one clinic in Mississippi, a southern state with three million inhabitants.
"Knowing that a correction of Roe is unlikely in the immediate future, we've done a lot of work at the state level and we think we're running one state at the time," said March For Life president Jeanne Monahan.
"It's not so much a change in strategy as a sophistication... We've seen more people self-identifying as pro-life and especially young people."
Despite emotions still running high over the issue, activists do not resort to killing doctors as took place in the 1990s.
"They were lone wolves, they were operating on their own, insisted Kelley.
"Abortion is never going to be resolved completely; it's something that civilization is going to have to deal with maybe forever."© 2013 AFP