In the geometry of District politics, there is one blind assumption that underlines all the equations: final jurisdiction over the city lies with Congress and the White House.

The assumption may no longer be valid. Where it once took an act of Congress even to name a city street, Congress' first instinct now is to have nothing to do with the District. Why run the risk, as did Rep. Charles Wilson (D-TEX.), of getting involved in city politics only to be accused of racism and real estate speculation and to be identified as the heavy opposition to the forward-looking cause of full political and fiscal autonomy for the city?

Even for a congressman interested in risking attack for the privilege of being the city's czar, there are not the "perks" of power that once went with the job. The political kitty of money that once flowed freely from the city's business community to a congressman who listened and helped with problems is now diverted to fund political campaigns for the mayor and city council.

"Does the Congress run the District?" Rep. Julian Dixon (D-Calif.) says, repeating a question. "Historically that might be right. But now there is very little control and it's getting less and less. We have nothing to do with the day-to-day operation. . . . I don't want to know if the District Building is out of toilet paper."

"Generally, the feeling is let the District do what it wants," says Sen. Patrick J. LEAHY (D-Vt.) head of the Senate Appropriations Committee's subcommitte on the District of Columbia. "Look at the Convention Center. That thing is a turkey. It won't break even for five years. I argued it until I was sure the federal government wasn't going to get stuck with the bill. If that ever happened, I'd be to blame. But if I controlled the District, it wouldn't ever have been built. If I controlled the District, you wouldn't have 8,999 no-right-turn-on-red signs around here."

While Congress is not the almighty power it once was, there is still a push to get it completely out of local affairs. But some city residents, surprisingly, do not want Congress completely out of city politics.

On radio call-in shows and in private conversations, some city residents, city department heads, business leaders and clergy say it is a good thing that Congress is here to ask the mayor questions about the budget crisis.

"What you've got to understand," says one longtime District resident and actor on the political scene, "is that Congress was a back door that suited people who had the key . . . . Now it suits people who don't have full faith in the people in the District Building. The Congress checks up on them."

When Congress was in full flower as ruler of the nation's capital, it was a court of final appeal for city residents when the often lethargic city bureaucracy wouldn't pick up the trash. Businessmen had an easy avenue of power to use to get city agency directors to do what they wanted. Agency heads paid attention when congressmen spoke or when they didn't have money to run their departments. There was no mayor. The system was not democratic, but for some individuals it was effective -- they had a way to get things done.

It is not only certain District residents and businessmen who like having Congress as the overload of the city. A lot of District politicians, in their heart of hearts, are not so displeased with the system either. Congress is a favorite local scapegoat.

"How many of you know the names of the people on the four District committees?" Mayor Barry asked a graduation day crowd at the University of the District of Columbia in a speech urging city residents not to criticize black leaders. "That (Congress) is where the power is. It doesn't take much courage, much guts or much brains, quite frankly, to march down to the District Building against me."

But despite claims from local politicians that Congress is the ultimate power in the city, the reality of Congress' power over the District today is that senators and congressmen no longer have a hand in running the buses, zoning the land and passing the laws; Congress is a strong but silent partner in city operations. Its members can say no. But they almost never do. They come in once a year to check the books, and the rest of the time they do little but stick their heads in and offer a critical remark if the city government is not going well.

Where congressmen once enjoyed the prestige of power over the nation's capital, now even the most junior members of Congress try to avoid District committee assignments. What a congressman gets out of being on a District committee today amounts to experience for new congressmen who couldn't get a committee chair otherwise; the right to oversee the staff members on District committees; the opportunity to tell voters back home what they are helping to keep federal spending down by keeping the District's budget lean; and, for Maryland and Virginia members, the chance to keep the commuter tax out of law. As long as Maryland and Virginia have congressmen and as long as Congress has any say over the District, the city will not enact a tax that takes money from Maryland and Virginia residents who work in the city. That is the hardball political reality of running a local government in the nation's capital more than intervention in local affairs by Congress.

"We don't get many calls from Congress on day-to-day things, even some of the big stuff," says Ivanhoe Donaldson, special assistant to the mayor. "I might get a personal call on a parking ticket. They will send it over with the sergeant-at-arms and we arrange it so they don't have to appear in court. Or they might call about some bureaucratic problem they're personally having with a city agency. We'll try to speed things up for them. You don't want them to get mad at you. But that's about as far as it goes."

What unquestionable power Congress does hold over the District is the power of the purse string -- Congress legally could control every penny spent by the city government. It can go over the budget line by line, adding policemen or objecting to two campuses for the University of the District of Columbia. But budget officials, both in the District Building and on the Hill, say that Congress has chosen not to fully exercise that one remaining power in the last few years.

With the exception of the size of the police force, Congress' review of the budget for the past few years has been limited. The city's priorities for spending are studied philosophically, as in the case of whether a second campus is needed for UDC. Occasionally, a national lobbying group, such as Right-to-Life, makes its weight felt. But no such group has ever won over objections of city officials. The close, agency-by-agency scrutiny of the city budget, which was key to Congress' control of the city, is a thing of the past.

It is so far gone that although most congressmen still appear to think the city government is badly run, they keep their mouths shut, generally.

"I won't comment on the operation of the city government," says Rep. Dixon. "What problems they've got are their own . . . . I'm not a voter here. I will go as far as to say I think they could do a better job with education. And obviously there is concern about the level of police staffing."

Sen. Leahy, too, is reluctant to criticize the District government. "I don't think it's news that the District government has a long way to go, he says. " . . . I've told Marian to go ahead and use Congress as a scapegoat to get some things done that are long overdue, like cutting the size of the city work force . . . . If I had to list three priorities for the city government, it would be firing some people -- they've got too many -- changing the tax structure to encourage business to come here and improving the schools.

"I travel around the city to see what is really happening. I notice the license tags at the construction sites are all from out of town. The city should be training local people to take those jobs . . . . Another thing I notice is the difference in this town between the haves and the have-nots. It is startling."

If Congress is the silent partner in the District government, there is a near-invisible partner, the White House. Like Congress, the White House has power over the city budget. The District budget is submitted to Congress as part of the president's budget, and the White House could make changes in it. But it doesn't. The White House also appoints members to the Pennsylvania Avenue Development Commission and the National Capital Parks and Planning Commission, as well as selecting local judges and the U.S. attorney.

But in addition to its not making any changes in the city budget for several years, the White House is backing a proposal to grant the city full budget autonomy and to make the federal payment to the city an amount determined by formula. That essentially would take the White House out of any role in the District's budget. The White House is also working to give the city an independent judicial system.

The White House only recent split with the city government came on the appointment of a U.S. attorney last year. The man awarded the position was not the nominee of the city's leaders.

"The city got itself in a bad position on that one, said Pauline Schneider, a staff assistant at the White House for intergovernmental affairs. "Instead of sending us two or three candidates that were acceptable to them, they got behind one who we had some questions about."

In the past, Schneider's post at the White House was held by people who tended to District affairs exclusively. Now Schneider keeps an eye on District affairs as part of broader duties. The District is not the priority item it once was at the White House.

"We don't like to get involved in local politics here," said Jim Dyke, special vice presidential assistant for domestic affairs and former campaign manager for Clifford Alexander, who lost the 1974 mayoral race to Walter Washington. "Given the District's unique historical situation, we've got to be careful."

With Congress and the White House giving the city greater independence -- by not closely reviewing the budget or tinkering with the city's day-to-day operations -- the District is now in a new political posture. It is essentially free to do as its political leaders want; the only fear is that Congress or the White House could exercise absolute power over D.C. affairs.

So no one is behind them with a club now. But city officials still find themselves looking over their shoulder, as they did in the past, for someone to overrule them.

If District officials fear what might be behind them, in the shape of federal authority, what is ahead of them is equally scary -- maybe worse: full power over city affairs with no one to blame if they can't run the city properly. And this is the point.

City officials have never had to fly on their own. They are accustomed to pointing at Congress, complaining about this senator, shouting about the inadequacy of the federal payment and how they must kowtow to Congress. But they are shouting at the past.