"A mayor does everything," Marion Barry said, as I hopped into his chauffeured car for a day with the mayor last week. "We maintain roads. Purify water. Did you know the District has 600 parks? People confuse a lot of our stuff with the feds. But the things that make this city work, we do it. We do it all."

The mayor had just downed a glass of Dick Gregory's Bohemian Diet Drink. He was psyched up and preparing to convince Sen. Arlen Specter (R-Pa.) that he was doing it all -- and doing it well.

We were headed for Specter's D.C. appropriations subcommittee hearing on Capitol Hill. Within the span of a mile, Barry would undergo a major transformation, from arrogantly overseeing a $2 billion budget to humbly explaining how the money was being spent.

"I don't necessarily like making this trip," Barry said, as he splashed on Tuscany cologne and adjusted his necktie. "But I do it better than anybody else in this city."

Then the car telephone rang. A department official had some numbers on public housing that made the mayor wince. "Maybe the hearings will take a philosophical direction," Barry hoped. "I could say we believe that people should pay their rent -- and I could add how hard it is to attract top administrators because people just don't want to take all of that [stuff]."

"Stuff" sounded like he meant scrutiny. On his desk at the District Building, Barry kept a copy of "The Washington Pest," a parody of a newspaper that reported stuff like mismanagement in his housing department.

"People just don't know how complicated it is to run a city like this," Barry said. "If we could just get half of what the federal government should be paying us in taxes . . . . We're just lucky to have four good chairmen on the House and Senate District committees."

The mayor was obviously rehearsing, keeping himself pumped up.

Barry was greeted like a minor foreign dignitary when he arrived on Capitol Hill. Traffic was stopped as his car made a U-turn and parked in front of the Russell Senate Office Building. After the mayor was seated at the hearing table, Specter entered the room like a judge from a door behind the dais.

"Mr. Chairman, we appreciate the attention that you have devoted to our city," Barry began in a slow, mellow tone. He would say Specter was "appreciated" at least four times. "I agree with you that we should be a model city," Barry continued.

The mayor was on a roll, and Specter was nodding in agreement. Even when the mayor admitted that he had made mistakes that resulted in prison construction delays, Specter seemed to understand. And when the moment seemed just right, Barry made a subtle pitch for $20 million more in federal funds.

All was going smoothly until City Council Chairman David Clarke told Specter that Barry was "talking out of two sides of his mouth" on the matter of prison construction delay. But it was too late for Clarke.

"If you don't like what the mayor is doing, submit your own plan," Specter told Clarke curtly. At any rate, Specter added, "I don't want to hear anymore about this now."

"Thank you," the mayor said to the senator, "for what is often a thankless task. You have given it all you have. The people of Pennsylvania are fortunate to have you."

Specter flushed.

"You may have to help me tell them that at election time," the senator said.

"I wouldn't mind that at all," Barry beamed.

Upon returning to the District Building, Barry telephoned the city's public works department. On the way home, he had spotted two broken water fountains in a park at First Street and Florida Avenue NW. Before the day ended, the fountains were fixed.

It was one day when Barry had done it all.