WASHINGTON — Over 100 Yale students and New Haven residents joined thousands of demonstrators from around the country here early Tuesday to rally and march in defense of affirmative action.

On Tuesday morning at 1 a.m., Yale students and local residents, pillows and blankets in hand, boarded two chartered buses in New Haven bound for the nation’s capital. The protest, organized by Fight for Equality By Any Means Necessary, United for Equality and Affirmative Action and the Coalition to Defend Affirmative Action & Integration, drew a crowd of over 5,000 people. The two Yale buses were sponsored by the Yale cultural centers and the Black Law Students Association.

Students and residents joined other protesters at a rally on the steps of the U.S. Supreme Court; inside, justices heard oral arguments in Grutter v. Bollinger and Gratz v. Bollinger — two landmark cases that could eliminate affirmative action policies in college and law school admissions.

In the cases, three white applicants rejected by the University of Michigan and its law school are challenging the school’s admissions policies as unconstitutional racial discrimination. They contend that black, Hispanic and American Indian candidates with the same qualifications are given preferential treatment.

Justices questioned the university’s lawyers Tuesday about whether the school’s affirmative action policies could be considered part of a quota system. In 1978, the Supreme Court outlawed the use of quota systems in admissions systems at tax-supported universities.

Diego Bernal, a second-year law student at the University of Michigan, had been involved in the battle for affirmative action long before he ever set foot in front of the Supreme Court Tuesday morning. He has had the unique experience of viewing the case from both the center and the periphery of the discussion.

“We’ve been thinking about [affirmative action] a lot — we’ve been entrenched in it,” Bernal said. “It’s great to see other people, strangers, care as much as you do.”

The “strangers” Bernal referred to included the busloads of affirmative action supporters from Yale and New Haven. Despite a restless five-hour ride from New Haven, the weary travelers were full of enthusiasm for the day’s upcoming events.

“I’m so excited,” said Julie Gonzalez ’05, one of the trip’s coordinators, early in the morning. “It’s awesome that people are coming together behind an issue. It’s amazing.”

Signs and banners filled the air as civil rights and student leaders charged the steadily growing crowd with calls for unity and strength in diversity. “They say Jim Crow, We say hell no!” could be seen on signs throughout the crowd. Some signs went so far as to equate the battle for affirmative action with the historic civil rights battle for desegregation: “Save affirmative action, protect Brown v. Board of Education.”

The widespread ramifications of the cases were reflected in the generational and geographic diversity of the crowd.

“What’s surprising is the generational distribution,” Bernal said. “There are professors, young professors, grads, undergrads and high school students here.”

Brian Flores, a freshman at the University of California at Berkeley, flew out to the capital along with over 200 of his classmates while school was in session just to participate in the march. He said he was struck by the nationwide student participation at the rally.

“I’m very impressed by the solidarity of the students,” Flores said.

Union members in favor of affirmative action joined students in large numbers.

“The representation of labor is overwhelming,” said Peter Romer-Friedman, a legislative representative of the United Steelworkers of America, as workers sang “We are the unions.”

At 11:15 a.m., protesters filed out of the rally point in front of the Supreme Court onto a cleared Constitution Avenue and began to make their way toward the Lincoln Memorial.

“I’m hoping to see [Supreme Court Justice Sandra Day] O’Connor peek her head out the window,” Jeremy Butler, a second-year law student at Georgetown, jokingly said. “We need her vote.”

Justice O’Connor and Justice Anthony M. Kennedy are widely considered the crucial swing votes on affirmative action issues.

Marching down Constitution Avenue, demonstrators made their voices heard. They chanted, “What do we want? Affirmative action! When do we want it? Now!” and “I know I can be what I want to be, unless you take affirmative action from me!”

A small anti-affirmative action contingent was also present. Three men stood on the side of the road holding signs that read “Affirmative action breeds incompetence” as demonstrators walked by.

But affirmative action was not the only issue on demonstrators’ minds.

Marchers were greeted at the steps of the Lincoln Memorial by speakers blaring Edwin Starr’s classic anti-war song “War,” and signs reading “Send us to school, not war” were interspersed with the affirmative action messages.

“Affirmative action colluded with the anti-war movement,” Flores said.

But, as Chiraag Bains ’03 pointed out, the bulk of campus energies have been focused on the war in Iraq and the recent Yale labor strikes.

“Not everyone grasps the urgency of this issue,” Bains said. “This will have consequences for higher education.”

A decision in the case is expected in late June or July.

— The Associated Press contributed to this article.