Tens of thousands of demonstrators committed to banning abortion in America marched to the U.S. Supreme Court yesterday in what for some was a depressingly familiar route they had followed 25 times before.

But this year, many said, the upcoming presidential election buoyed their hopes that the end of legal abortions is near. And the Supreme Court's decision to hear a challenge to certain late-term abortion procedures was further cause for optimism that there might soon be a ban on what opponents regard as "partial birth" abortions.

"I think we're very close to getting the law changed," said Mark Wildness, 23, who has been attending the annual March for Life since he was 12. A new president, he said, could make all the difference.

Wildness, like all those interviewed yesterday, said he also opposes artificial birth control. "If you go according to God's law, birth control should not be legal," he said.

Joe DeLucia, who brought 36 teenagers to Washington from St. Mark's Catholic Church in Emporium, Pa., said the candidates' stance on abortion is the primary issue on which they should be judged. The five Republican presidential candidates support a ban on abortion; none of the Democrats do.

"The liberal attitudes of the current president are going to be swept away by a new conservative president, and Roe v. Wade will be swept away, too," said DeLucia, referring to the 1973 Supreme Court decision that guaranteed a woman's right to have an abortion.

Once abortion is outlawed, DeLucia said, his young charges nodding in agreement, the movement can turn its attention to making birth control illegal--although he doubted that push would be as aggressive.

The demonstrators were exceptionally polite and subdued. The crowd was overwhelmingly white and, judging from banners, prayers and conversations, predominantly Roman Catholic.

The small bands of hecklers that have dotted the protest route in past years stayed home yesterday, making for a quiet march. There were no arrests.

Edward Richie, of York, Pa., has helped carry the statue of Our Lady of Fatima every year since the march began in 1974. Bruce and Barbara Stahl, of Voorhees, N.J., first came when their then-youngest son was a baby. The boy is now 12 and was there yesterday with four younger siblings.

The Stahls said they hoped this might be the last, or next to last, march they have to attend. But even those without such optimism said their presence was important.

"I don't know how much good it's doing, but one feels you have to make a statement at least," said 73-year-old Anne O'Reilly, of Front Royal, Va. O'Reilly was at the first march and came yesterday with 15 of her grandchildren, none of whom was born when reproductive choice was made the law of the land.

Orange signs saying "The Natural Choice Is Life" competed in number with blue signs quoting Pope John Paul II, who has called abortion "The Most Unjust Execution." Some carried grisly photographs of what they said were aborted fetuses.

A handful of protesters also championed other causes. Dorman McKinney, 72, for example, drove a rattletrap 1969 vintage bus from Texas to rail against abortion, the Panama Canal Treaty and "sodomites."

And members of the Pro-Life Alliance of Gays and Lesbians marched behind their group's banners, despite being ordered by march organizers not to identify their affiliation. The group of about 20 simply stepped into the march a block or so beyond its starting point.

The march was the culmination of three days of prayer and protest that began early Saturday outside Planned Parenthood of Metropolitan D.C.

Jatrice Martel Gaiter, president of the family planning group, yesterday said that Roe v. Wade did not invent abortions but merely made them safe. Her clinic workers, she said, "do much more to prevent unintended pregnancies than any amount of sign holding, harassment or pavement preaching. We work every day to make sure every child is wanted, nurtured and loved."

Organizers said 80,000 to 100,000 attended yesterday's march. There was no independent verification of the estimates. The U.S. Park Police stopped making crowd estimates several years ago after organizers of various events vehemently challenged police counts as being too miserly.

As he marched with the crowd, Dick Wilson, of Massillon, Ohio, said he wasn't counting on a new election so much as on a miracle. He goes to Mass at least three times a week to pray for an end to abortion.

"The majority of people are for abortion; the majority of Congress is for it," Wilson said. "But I just look at how communism was overthrown without bloodshed. That had to be a miracle, and I don't see why we can't have another miracle here."

Many parochial schools throughout the country arranged trips on buses, planes and trains to bring young people to the march. Melanie Murosky, 17, said she has "always been pro-life" but got more involved after joining the Pro Life Club at Seton Catholic High in Pittston, Pa.

"You should have to deal with your mistakes," she said.

Erin Bauer, 15, of Notre Dame High School in St. Louis, said her parents paid the $275 for her trips this year and last. She sees commercials, she said, that say "it's a choice; this is a choice. Well, having sex and getting pregnant is the choice."

Abstinence was a major theme of the youth rallies that preceded the march. At Constitution Hall, the Rev. Stan Fortuna, a bearded, rap-singing Franciscan, had the capacity crowd of 4,500 swaying: "Your body is the Lord's/Your body's not your own/Media want to drag you down/To the zipper zone."

CAPTION: Antiabortion marchers, many carrying signs, proceed up Constitution Avenue. Organizers estimated the attendance at 80,000 to 100,000; police did not provide an estimate.

CAPTION: Briget Sloas shouts a slogan encouraging other marchers as they pass the Supreme Court. Many demonstrators said they hope the presidential election will mean an end to abortion.

CAPTION: A marcher pauses for a yawn before rejoining the throngs in front of the Supreme Court to protest Roe v. Wade, the court's 1973 decision that guaranteed abortion rights.