Key congressional Democrats signaled strong approval yesterday of Sharon Pratt Dixon's victory in Tuesday's Democratic mayoral primary, and indicated a readiness to assist the financially troubled District should Dixon prevail in the November general election.

Senate Majority Leader George J. Mitchell (D-Maine) called Dixon in her hotel room Tuesday night to offer his support, and that was followed by a steady stream of calls yesterday from other prominent Democrats, including Sen. Edward M. Kennedy (Mass.), Sen. Brock Adams (Wash.), Rep. Charles B. Rangel (N.Y.), and Rep. John Conyers Jr. (Mich.).

"I haven't talked to anybody here today who doesn't believe this is a new beginning," said Rep. Julian C. Dixon (D-Calif.), chairman of the House D.C. appropriations subcommittee. "Her campaign rhetoric about cleaning house appeals to many members of Congress. They want to assist in any way they can."

In a speech on the Senate floor, Sen. Barbara A. Mikulski (D-Md.) urged her colleagues not to try to "micro-manage" the District in the process of providing the city with additional resources. Mikulski also hailed the victory of Eleanor Holmes Norton in the Democratic primary for D.C. delegate.

"Let's give the new leadership a chance," she said. "I ask my colleagues who have used the District of Columbia appropriations {bill} as vehicles for other social agendas to really have a new attitude."

The show of support -- a marked contrast to the testy relations between Congress and the Barry administration -- is extremely important given the likelihood that the next mayor's most difficult task will be coping with the city's mounting budget problems.

The District, which faces a $100 million budget deficit this year, is likely to run out of money at some point next year without an infusion of revenue or deep spending cuts, according to D.C. officials.

"The next term is going to be incredible," said John A. Wilson, who won the Democratic nomination for D.C. Council chairman in Tuesday's voting. "We're going to have to make some really hard decisions . . . . I think the budget has to be cut. I think whole programs can be cut."

Julian Dixon, no relation to the Democratic nominee, said it would be in the national interest to boost the federal payment to the District, as legislation currently before the House would do.

"If we don't help them in the short-term, it is going to be a heavier burden later on," he said.

In recent years, Congress has appropriated increased funds for specific tasks, such as hiring 700 new police officers, but has kept the basic federal payment at $430 million.

That payment, in lieu of taxes, is designed to compensate the District for services it provides to the federal government. But many members of Congress, disgusted with reports of corruption and mismanagement within the Barry administration, have said there was no possibility of increasing the sum until Barry was out of office.

Adams, chairman of the Senate appropriations District subcommitee, said Dixon would have an opportunity to gain an increased payment as mayor if she can demonstrate that she is reducing waste and mismanagement and improving city services.

"People want to feel that they are getting something for their money," Adams said.

Dixon, a former treasurer of the Democratic National Committee, has said that her ties to many congressional Democrats would help in the city's quest for an increased federal payment.

But the ascension of a new mayor, whether Dixon or Republican nominee Maurice T. Turner Jr., will not guarantee an increased payment, officials caution, in part because the federal government is grappling with its own fiscal problems.

Also, if she wins in November, Dixon would face a high hurdle in fulfilling her campaign promises. Dixon has promised to cut the "fat" in the District bureaucracy, starting by firing 2,000 middle- and upper-level managers, and says it would border on "criminal" to consider new taxes.

While many politicians agree that the city's 48,000-member work force is "bloated" and "inefficient," most experts on the city's finances say that Dixon's campaign promise about immediately firing 2,000 workers is unrealistic.

"You cannot fire 2,000 people unless you have cause," said Wilson, chairman of the Finance and Revenue Committee and widely regarded as the council's leading expert on city finances.

Similarly, several politicians are skeptical about Dixon's pledge to hold the line on new taxes. While there is strong sentiment on the council against new property or income taxes, council members are likely to reconsider other ideas, such as a tax on professional services.

"Either she'll have to get more money from the Congress, or she'll have to find new revenues," said council member Jim Nathanson (D-Ward 3).

As a come-from-behind victor, Dixon would have one singular advantage coming into office: the fact that she was not supported by labor, business or the social service lobby, special interests that often make it difficult for mayors and legislators to cut budgets.

On the other hand, Dixon would have to secure cooperation from a council that has grown more assertive in recent years and that may become more assertive if Barry wins an at-large seat.

Wilson already has served notice that he intends for the council to be a "co-equal" branch of government. He is proposing that the next mayor, council members and the school board sit down to try to forge a consensus on how to solve the city's fiscal problems.

Staff writer Mary Ann French contributed to this report.