Alarmed by recent political setbacks, abortion-rights supporters are trying to channel election-year anger at President Bush into what they hope will be their largest protest rally ever.

Organizers of Sunday's "March for Women's Lives" -- which include Planned Parenthood (search), the National Organization for Women (searchand the American Civil Liberties Union (search-- are seeking a turnout in Washington exceeding the estimated 500,000 who attended an abortion-rights rally there in 1992.

That year, the protesters' paramount concern was the U.S. Supreme Court (search), which was considering a case that could have resulted in overturning a woman's right to abortion. This year, the focus is on Bush -- and on a wave of legislation passed by Congress and state lawmakers that march sponsors say is incrementally chipping away at the same right.

"I remember thinking in 1992 that women's reproductive rights couldn't be in any greater jeopardy, but now they are," said NOW President Kim Gandy. "We're sounding the alarm -- we want to invigorate a whole generation to take action to protect the rights that their mothers fought for."

Bush, whom march organizers call "the most anti-choice president" in history, has signed two pieces of legislation since November long sought by anti-abortion activists.

One, the Partial-Birth Abortion Ban Act (search), is now under challenge in federal court; it seeks to outlaw a procedure which critics say is barbaric and which defenders say is sometimes the best option for preserving a woman's health. The other, the Unborn Victims of Violence Act (search), is the first federal law to endow an embryo or fetus with legal rights distinct from the pregnant woman.

Beyond these new laws, abortion-rights supporters fear that Bush, if re-elected, would have a chance to fill Supreme Court vacancies with justices who would help overturn the 1973 Roe v Wade ruling that made abortion legal.

Anti-abortion groups have been busy organizing counter-demonstrations to coincide with Sunday's rally.

"The March for Women's Lives is a 'death march,' and we will be there to confront them with the truth," said Randall Terry, founder of the anti-abortion group Operation Rescue (search).

Beyond the federal arena, abortion-groups are dismayed by the scores of state laws passed in recent years that make abortion less accessible. These include mandatory waiting periods, requirements that girls under 18 notify their parents, and other restrictions that have closed abortion clinics or induced doctors to cease providing abortions.

Erica Dhawan, 19, of Pittsburgh, said one of her biggest concerns was the Bush administration's push for abstinence-only sex education.

"They're fostering a distrust of women and a distrust of young people," said Dhawan, a University of Pennsylvania freshman who will be attending a pre-march conference aimed at mobilizing activists under 30.

A conservative policy analyst, Janice Crouse of the Beverly LaHaye Institute (search), contended that public support for abortion is diminishing and hoped for election results that would produce tighter restrictions.

"If we re-elect Bush and a pro-life House and Senate, it's inevitable that the laws will reflect the makeup of the people that are there," she said.

March organizers say more than 1,300 national and local groups have lent support to the rally. Celebrity supporters include Whoopi Goldberg and actress Helen Hunt.