Minutes after the D.C. Council rejected the Barry administration's tax proposals in March, Budget Director Richard C. Siegel warned that the council was only delaying the "inevitable" until after the fall elections.

Two months later, Siegel's prognosis appears to have been on the mark, as the city's financial condition continues to deteriorate.

Three weeks ago, the city's bond rating was lowered by a major Wall Street rating agency, the first such action since the city began issuing its own bonds in 1984. Perhaps even more ominous, city officials reported last week that tax collections for the year were off $28 million from earlier projections.

The fall-off in revenue is yet another indication of the sagging regional economy. District officials have known for some time that the problems facing the local economy would spell budgetary trouble for the city, but it now appears that the decline is even quicker and more precipitous than forecasters had predicted.

As one local finance expert commented this week, "The situation for the city is getting worse, quicker."

But you wouldn't know that from the mayor's office, which recently authorized the expenditure of $17,000 for a boat ride down the Potomac and $2,000 for Effi Barry's trip to the Cannes Film Festival. Nor would you know it from the rhetoric of politicians running for office this year, most of whom have avoided any serious discussion on how they would solve the District's financial mess.

Several mayoral candidates, particularly Sharon Pratt Dixon, have talked about slashing what they call the city's "bloated bureaucracy," but none have offered specifics about which city programs they would cut or let go.

Similarly, no one appears to be particularly interested in talking about the need for tax increases, even though such increases seem to be all but certain after the elections in November.

Although the council passed what ostensibly was a balanced budget for fiscal 1991, the budget did not include money for pay raises for teachers and other government employees -- raises that could cost $50 million or more. With revenues falling off sharply, the District could be facing a deficit of more than $70 million for 1991.

Without action, the deficit is projected to grow to $160 million by 1992 and to $375 million by 1995, according to recent city projections.

While most politicians are quick to blame Congress for the failure to increase the federal payment to the District ($430.5 million this fiscal year), the hard truth is that the federal government has neither the means nor the inclination to hand over more money to the District these days.

That leaves either drastic spending cuts or a tax increase -- but not until after the election.

D.C. Council member John A. Wilson (D-Ward 2), who is running for council chairman, is one of the few politicians who has been talking openly about the fiscal morass the city is facing. (He is also one of the few politicians who is facing a relatively easy campaign.)

Wilson said last week that there is "no incentive for people who are running now to do anything" about the city's financial problems.

But Wilson predicted, "It doesn't make any difference who is elected mayor. They're going to have to pay off 20 percent of the work force or raise taxes by $300 million." Goodbye to a Wizard

Billy Cooke, the city's wizard with financial numbers, is calling it quits after 21 years in District government.

Cooke has been in charge of one of the most important, if least understood and appreciated, tasks for the city government: estimating the amount of taxes the city expects to collect every year.

Cooke's estimates are the basis of the budgets prepared annually by the mayor and the D.C. Council, and over the years Cooke has earned a reputation for integrity in a field that is susceptible to political manipulation.

Cooke's is the latest in a string of departures by some of the city's most experienced bureaucrats.

While the departures may be seen as natural for the final months of a mayoral administration, they are undoubtedly severe blows to a government already distracted by the travails of the mayor.

Cooke, who is leaving to become executive director of the Institute of Property Taxation, emphasizes that his departure has nothing to with "contemporary affairs," but rather with his desire to take advantage of a career opportunity. "I'm not mad at anyone," he said, offering only high praise for Barry and other city officials. "Marion Barry never asked me to change a damn figure." From a revenue estimator, that's high praise indeed.