For a number of winters, the closest neighbor to the president of the United States was a homeless man who slept on a sidewalk heat grate not far from the southwest corner of the White House lawn. Now there are some new neighbors--about a dozen of the homeless poor who spend the night in campsite tents in Lafayette Park, the beautiful acreage of lawns and gardens facing the north front of the White House.

By yardage, the new neighbors are closer to the world's most powerful political leader. By symbolism, the gathering of the poor and their tents--called Reaganville--is a public protest against political decisions whose end effect is to push more and more citizens into street poverty.

For many, it is worse. Not far from the tents is a symbolic cemetery of 539 white crosses imbedded in the lawn to memorialize the nameless poor known to have frozen to death in 11 cities in the past five years.

Reaganville is not a pretty scene, as the Hoovervilles of 50 years ago were not either. Lafayette Park being federal Interior Department property and the neighbors across Pennsylvania Avenue known to be connoisseurs of the good life, this encampment was not an occasion for the welcome wagon. The legal background of how Reaganville came to be is as compelling as the stories of the poor themselves.

It began on Sept. 30, 1981. An official from the National Park Service of the Interior Department denied the application of a local community group and 10 poor people to use Lafayette Park for a four-month demonstration on behalf of the homeless. The park, the government argued, is regulated by a no-sleeping ban.

The group--the Community for Creative Non-Violence, a Catholic Worker-type organization with a 10-year record of feeding and caring for the poor of the nation's capital--filed suit in U.S. District Court for the District of Columbia. On Nov. 25, the judge upheld the Interior Department's denial to camp.

Five days later, the community group won the government's permission for a seven-day demonstration in the park, including the erection of nine tents in "a symbolic campsite." But the sleeping ban continued.

On Dec. 18, the community group's lawyers returned to district court. The judge was Charles J. Richey Jr., an Ohio Republican appointed to the bench by Richard Nixon. The lawyers argued that the poor had a constitutional right to sleep in the tents. The demonstration, they said, "is a powerful exercise of free speech. The homeless have chosen a dramatic mode of expressive conduct in the conviction that nothing short of their ongoing presence in Lafayette Park, not just empty tents, is an effective statement. That choice falls within the broad ambit of the First Amendment."

Ruling in the case, called Community for Creative Non-Violence v. James G. Watt, Secretary of Interior, Judge Richey decided on Dec. 23 for the poor and against the government: Sleeping in the tents "is a means of symbolic expression of their First Amendment rights."

The Richey decision, which said in essence that a citizen's right to demonstrate shouldn't be denied because he must sleep, was appealed by the government.

On Jan. 22, the U.S. Court of Appeals for the District of Columbia upheld the Richey decision. "We believe," the three appeals court judges wrote, that "the Park Service regulations plainly allow the (poor) to sleep in the tents as an intrinsic part of their protest against governmental policies which they allege contribute to their lack of shelter. . . . Moreover, as the District Court found, in this case sleeping itself may express the message that these persons are homeless and so have nowhere else to go."

The defeat of the Interior Department is nothing to cheer about. The case has meaning only if "the message" referred to by the court of appeals is heeded by the president across the street, Congress across town and public officials across the country.

Not to respond is to guarantee the accuracy of a sign at the entrance of Reaganville: Population Growing Daily.