If 1 million men actually show up in Washington Monday for the Million Man March, Nation of Islam leader Louis Farrakhan will have staged an event of truly historic proportions.
It will easily dwarf the 1963 March on Washington during which Martin Luther King Jr. delivered his immortal "I Have a Dream" speech. It will eclipse the massive anti-Vietnam War rallies of 1969 and 1971. And it will far exceed all Washington marches on behalf of gay rights, pro-choice, anti-abortion and labor solidarity.
In fact, aside from the inauguration of Lyndon B. Johnson in 1965 and the Bicentennial celebration in 1976, Mr. Farrakhan will have orchestrated the biggest gathering in the history of the capital.
And he will have done so with not one but two daunting handicaps.
Mr. Farrakhan is issuing invitations only to those who are black and male. To satisfy its billing as a Million Man March, organizers will have to produce one out of every 15 black American males, including children.
Already, the organizers have started their spin control in the likely event they do not realize their lofty numerical goal.
"If we match the 250,000 [200,000, according to the U.S. Park Police] of the 1963 march, it would certainly be a success," said the Rev. Benjamin F. Chavis Jr., the former NAACP leader who is directing the march.
"If twice that number comes, it would be an overwhelming success. If we get a million persons, it would be the largest First Amendment demonstration in American history."
Even if the numbers are smaller, Monday's march promises to be singular. Never before in the 101-year history of major marches on Washington has there been one in which all the participants were African-American.
Monday's march will not achieve results, at least not in a conventional sense. Marches on Washington usually have the goal of wrenching policy changes from the federal government, whether it be to end a war, give women the vote, or increase aid to farmers.
But Monday's march does not have a stated policy objective, which may also make it historically unique. Its organizers say it is a "Day of Atonement" for black men; they have not presented any demands to the president, Congress or other governmental authority.
"It's kind of a moral mobilization," said Joshua Freeman, a Columbia University professor of modern political history. "But the participants see themselves as the actors rather than the president or Congress. In that sense, it's quite unusual."
In fact, the purpose of marching on Washington at all, rather than, say, New York or Bangor, Maine, is usually to seize the attention of policy makers.
That's certainly what Jacob S. Coxey, an Ohio businessman, had in mind when he organized what is generally considered the first march on Washington in 1894.
In the midst of the nation's first industrial depression, Coxey amassed unemployed men for a march to Washington in support of a federal jobs program. Called "Coxey's Army" and led at times by Mr. Coxey's daughter, a high school majorette, the group numbered about 500 when it reached the capital.
But while Mr. Coxey was delivering a speech on the steps of the Capitol, he and others were arrested for trespassing. The setback was serious enough for his army to lose heart. They evaporated, and so did their cause.
More successful was the 1913 march of 5,000 women in support of women's suffrage. It signaled a more radical turn in the previously polite suffrage movement.
Soon after, women were chaining themselves to the gates outside the White House and conducting hunger strikes in jail after their arrests. The public, and apparently President Woodrow Wilson, were appalled by accounts of the force-feeding of female prisoners. By 1917, Wilson was backing equal voting rights for women.
The so-called "bonus marchers" of 1932 got far less sympathy from their president, Herbert Hoover. During the Depression, as many as 15,000 veterans of World War I descended on Washington to lobby for accelerated payments of military pensions.
Unnerved by their presence that summer, Hoover ordered Gen. Douglas A. MacArthur to rout them from the city. General MacArthur did so, with bayonets, tear gas and tanks. It would be another six years before the doughboys got their bonuses.
In 1941, President Roosevelt managed to avoid what would have been the largest march on Washington, one planned by A. Philip Randolph, the great leader of the railroad porters union.
Randolph intended to bring a quarter of a million black men and women to Washington to force the president to guarantee jobs in war industries to blacks and also to integrate the military.
FDR recognized the march as a potential public relations disaster for his administration, which was then underscoring the repressive policies of the Nazis.
To avoid the march, the president established a commission to ensure jobs for blacks in the war industries. (He did not, however, integrate the military.) A triumphant Randolph canceled the march.
Twenty-two years later, Randolph was the honorary leader of perhaps the most famous Washington demonstration of all, the civil rights march of 1963.
Many believe that the show of strength and eloquence on display during that march were instrumental in passage of the landmark Civil Rights Act of 1964 and the Voting Rights Act of 1965.
That demonstration, which many consider the standard by which all others are measured, was not the largest. According to the U.S. Park Service, that distinction belongs to the anti-Vietnam War rallies of 1969 and 1971, which attracted 600,000 and 500,000 marchers respectively.
About 300,000 marched for gay pride in 1993, 200,000 for abortion rights in 1989 and the same number against abortion in 1990.
But political causes have not been the only inducements for hundreds of thousands of people to flock to Washington's streets.
In 1983, half a million turned out to celebrate a Washington Redskins Super Bowl victory.