Two out of three people who marched yesterday against the war with Iraq had participated in at least one other organized protest against U.S. policies in the Persian Gulf, according to a Washington Post survey of marchers conducted during the demonstration.

Interviews with 827 randomly selected marchers also found that an even larger majority -- nine out of 10 -- said they previously had attended a protest or demonstration for some political or social issue. One out of three protesters said they were veterans of anti-Vietnam War demonstrations during the 1960s and 1970s.

The survey also found that more than half the marchers questioned said they were "pacifists opposed to all wars," and not just the conflict in the Persian Gulf.

The statistical snapshot that emerged from yesterday's protest suggests that the typical demonstrator was a politically liberal, college-educated, 20- to 35-year-old man or woman from the northeastern United States.

Among the major reasons that marchers interviewed said they were protesting:One out of five said the Persian Gulf War is a senseless conflict with no clear objective.

One out of five said too many people would be killed.

One out of seven said the United States and its allies should have continued to rely on sanctions and diplomacy to force Iraq out of Kuwait.

Three out of 10 said they have a close friend or relative serving in the Persian Gulf. Nationally, about half of Americans polled have a close friend or relative in the Gulf.

According to the poll, more than seven out of 10 protesters were from outside the District, Maryland and Virginia, with about four out of 10 coming from three states: New York, Massachusetts and Pennsylvania. Only about one out of 10 marchers came from the metropolitan Washington area.

It also was a young crowd that collected in the shadow of the Capitol and marched 30 abreast up Pennsylvania Avenue NW, past the White House and down 17th Street to the Ellipse. The Post survey found that more than half of those who marched were younger than 35, while fewer than one out of 10 marchers was older than 60.

Three out of four marchers said they had a close friend or relative who might be drafted if the military draft were to resume. About a third of those marching yesterday were students working toward a degree.

One out of 10 said they were military veterans or serving in the reserves or National Guard.

Slightly more than half were women, mirroring national public opinion polls that consistently have found women are more likely than men to oppose the war with Iraq.

The marchers also were voters. Nine out of 10 said they were registered to vote, while national polls of adults find that about three out of four say they are registered.

Few marchers -- just 2 percent -- said they were Republicans, and 3 percent said they had voted for President Bush in 1988.

More than half of those interviewed said they were Democrats. Three in 10 said they were political independents. And one out of six belonged to some other political party. Nationally, slightly more than a third of all adults are Democrats, while slightly less than a third are Republicans and the remainder are politically independent.

About seven out of 10 marchers who were old enough to vote said they cast their ballots in 1988 for Democratic presidential candidate Michael S. Dukakis.

Eight out of 10 described themselves as politically liberal -- and half of those said they were "very liberal." Only 2 percent called themselves conservative, while about one out of 10 was politically moderate. Nationally, 28 percent of the country's voters describe themselves as liberal, and about 5 percent say they are very liberal.

Nine out of 10 marchers interviewed were white, while 9 percent were black. One out of seven marchers was Jewish, significantly higher than the proportion of Jewish Americans in the population as a whole.

Nine out of 10 marchers said they had attended at least a year of college, according to the survey. Nationally, about four out of 10 adults have completed one year of college.

To determine who was marching, and why, The Washington Post interviewed march participants during the height of the demonstration. The interviews were conducted between noon and 3:30 p.m. at key rally sites at the Capitol and the Ellipse, as well as along the march route. Late arrivals to the march and passersby attracted to the rally near the Ellipse that followed the march could not be included in the sample.

The techniques used to select those interviewed will, in theory, produce a random sample. But the difficulties of conducting a poll at such an event suggests the results should be interpreted conservatively.

Senior polling analyst Sharon Warden contributed to this report.