Feeding at the public trough took on new meaning the other day. Two hundred homeless or hungry people were allowed inside the U.S. Capitol to set up a one-day soup kitchen. This historic first occurred in a House Ways and Means Committee room. The poor had come to demonstrate in front of the Capitol, but when it rained and the event was canceled, an assistant to House Speaker Thomas P. O'Neill provided space.

As a sign of congressional largess, the Ways and Means Soup Kitchen offered help that was immediate, certain and definable.

Those blessings are not yet present--and may never be--in the federal government's two major efforts to help the poorest of the nation's poor. Last month, $100 million was allocated to food and shelter programs as part of the jobs bill. In January, the Reagan administration began looking for ways to turn over vacant federal buildings to the homeless.

In addition to the White House, four federal agencies are involved in Project Homeless: the Department of Housing and Urban Development, the Department of Defense, the General Services Administration and the Federal Emergency Management Agency.

On the bureaucratic face of it, nothing would seem less red-tapish than a program to get homeless people off the streets. Five years ago, it might have been asked, as it was: what homeless people? This past winter, when the media exploded with stories of freezing deaths and Congress held the first hearings in 50 years on homelessness, the population was finally identified. Yet three months after the Reagan administration announced its own awareness of the problem--the destitute sleeping on the sidewalks around the White House helped--no official in any of the four agencies could say with certainty that one homeless person was now being sheltered.

At HUD in February, Secretary Samuel Pierce sent a memo to regional administrators. Through local governments, charitable or religious organizations, they were to make "temporary shelter available for the homeless."

A deputy assistant secretary at HUD, whose responsibilities include housing for the poor, said she didn't know the results of the Pierce memo. Another official said the problem is being handled "regionally."

At GSA, which deals mostly in warehouses and office buildings, an official said he didn't know of any structures being turned over to the poor. A spokesman for the secretary of defense said he knew of no city where military buildings were now housing the poor. The White House Office of Private Sector Initiatives could offer no specifics on where homeless people were being housed. At the Federal Emergency Management Agency, an official said it would be another week before details were known about who gets what portion of the $100 million that Congress asked the agency to distribute.

Five hands are trying to steer this wheel. No one, though, seems to be mastering the directions, except heading toward the vague goal of sheltering the homeless. Every official, from HUD to the White House, expressed heartfelt concern. No doubt it is genuine, but a ton of concern doesn't equal a pound of results.

The Pentagon, for example, says it made offers of buildings in over 500 locations. That sounds as if the Department of Defense has become the Department of Mercy--except that large numbers of the sites are too remote or the utility bills too high. The Pentagon gift crumbs have been rejected or ignored by 485 cities.

Now that winter is over, homelessness is mistakenly seen as a seasonal problem. That no one dies of freezing in the spring or summer is an administrative illusion. This month and next are more crucial to easing the suffering of the homeless poor than anything to be done next winter. By then it is too late. Exposure deaths are uncommon in May but the government's decisions next month will mean life or death, or shelter or the streets, for the homeless a half-year later in November.

The fear among charitable groups that shelter the poor is that administrative inertia may set in. A bill was passed, memos were sent from high places. What more do the poor want? Now it's up to "the locals." In fact, those who have been sheltering the homeless are already straining under the demand. They see the federal agencies as only beginning their role, not putting it off as "regional."

With money committed, and groups available and eager to help, the last thing Project Homeless should become is Project Aimless.