BACK IN the bad old days before 1964, Southern sheriffs used to try to discourage civil rights marchers by warning that the police couldn't be expected to handle hostile crowds or ensure the marchers' safety. Often, when violence did occur, they blamed demonstrators for provoking the hostile reaction. None of this stopped the civil rights movement, but plenty of people were injured in the process.

On Sunday, the Ku Klux Klan is coming to town and expecting to march down Constitution Avenue, the traditional route of political demonstrators, from the Washington Monument to the Capitol. The Klan is just about universally despised in this community, and a number of citizens are expected to turn out just to hoot and jeer. The D.C. Police Department also believes that violence is a real possibility. But instead of preparing for the event and providing the officers necessary to keep the peace, the department seems to be sending the old Southern sheriffs' message: "You folks better not come to march, because we can't be responsible for what might happen to you."

The police have granted a permit to the Klan to march only from Seventh Street to the Hill and have suggested that since they cannot guarantee the demonstrators' safety on the longer route, the marchers stay on the Mall for the first half of the parade. The Park Police, though, has only 500 officers in this area, compared to the police department's 4,600, and cannot handle the job alone. The federal agency has asked the police to provide help -- which has never been refused before in such a situation -- and the police said it would be provided only in the case of an emergency. On Tuesday, the American Civil Liberties Union brought suit in federal court to compel the department to cooperate.

This city is not the Selma of the '60s. The nation's capital has handled enormous marches, colossal demonstrations and massive gatherings of controversial groups. Protection has always been provided, and the policy of the police department has been -- as it should be -- to ensure the safety of demonstrators notwithstanding the nature of their protest. The Klan's permit allows it to bring up to 300 marchers, but no one expects more than a couple of dozen. Guarding this pathetically small group would not appear to be so difficult.

It would be wonderful if the public simply ignored the sorry band of hatemongers or turned out with signs or silence to show contempt. But if there is trouble -- if the anti-Klan forces adopt the tactics of the old civil rights opponents -- the police must be there in force. The department has an obligation to protect the marchers and to keep the peace in the city.