It has been long years since a really large march stepped off from the Martin Luther King Jr. Center in Atlanta, bristling with placards and purpose. Who would ever have thought that, when one finally did, as happened last weekend, the thousands would be demonstrating in favor of discrimination?

Yet a demand for a constitutional amendment to bar gay and lesbian marriage was among the proclaimed aims of the event, a measure of just how much the issue of gay marriage has twisted us.

The march was sponsored by the New Birth Missionary Church, one of those trendy megachurches, in this case predominantly black, that wholesales faith. New Birth claims 25,000 members and from Saturday's turnout -- ten abreast and a half-dozen blocks long -- the claim is credible.

The church declared education reform, health care and wealth-creation in the black community as its broad goals but there seemed little doubt that the included agitation against gay marriage was a prime animator, and never mind that the pastor, Bishop Eddie Long, said the event did not intend ''to alienate or separate any group of people."

The two or three dozen counter-demonstrators didn't feel exactly embraced, however. They charged hate and homophobia, standard-issue rebukes, but neither seemed quite right and both are futile anyway, because the charges don't square with how most gay marriage opponents can see themselves.

''Confusion" and ''misunderstanding" would be more apt accusations, but they don't have much of a ring for street theater. Still, going beyond irony, the poignancy was strong when the intended victims of the proposed constitutional amendment broke into ''We Shall Overcome," the anthem of the civil rights movement.

This issue fractures us painfully and few places more sharply than in the black community, where some see gay rights issues as an extension of the civil rights movement and others see them as an affront to the movement.

Just look at the King family. The King Center did not endorse the march that used it as a stepping-off place, but the Rev. Bernice King, MLK's daughter and an organizer of the march, has said of her martyred father, ''I know deep down in my sanctified soul that he did not take a bullet for same-sex unions."

Her mother, on the other hand, the widow Coretta Scott King, has opposed a constitution ban, as have some other of the civil rights movement's old soldiers -- for instance, U.S. Rep. John Lewis, the former head of the Student Non-Violent Coordinating Committee, and the Rev. Joseph Lowery former leader of King's own Southern Christian Leadership Conference.

You can understand the disagreement over gay marriage. The idea is a surprise to just about all of us and offensive to some.

But however you feel about the marriage argument, there is something ineffably sad about seeing the shrine and the means of the transcendent civil rights movement being used to constitutionally cramp a class of fellow citizens for being just what God and nature make them to be.

Tom Teepen is a columnist for Cox Newspapers.