For three hours yesterday afternoon, Michael Roll, the mayor of District Heights, Thelma Santangelo, the wife of Prince George's state Del. Francis Santangelo and more than 100 other notable Maryland citizens sat in an Executive Office Building auditorium and listened to a parade of high Carter Administration officials discuss the problems of federal spending.

It was, said White House spokesman Jim Purks, a nonpolitical event. "It's intended to inform community leaders of what we're trying to do and give them a forum to express their views," he said. "I didn't see any political speakers on the list."

The gathering, four days before the Maryland primary, nonetheless did Carter's re-election campaign no harm if it impressed men like Baltimore State Sen. Joseph Bonvegna, the boss of a prominent political organization, or Baltimore County Del. Arthur Alperstein, who represents many of that area's undecided Jewish voters.

"The theme was kind of to tell us that we were in good hands with this administration," said Montgomery Del. Stewart Bainum, who was impressed but remained uncommitted to Carter.

And it served as another reminder of how Carter, as an incumbant president, has been able to win friends and supporters in primary state like Maryland in ways his opponents cannot match.

Although Carter has declined to campaign personally for Maryland's 59 convention delegates and his campaign managers only belatedly turned their attention to the state, the president has won dozens of endorsements -- and with them thousands of votes -- through a combination of White House perks and highly -- publicized federal gifts to the state in recent months.

The federal money has been especially noticeable in Baltimore, home to one quarter of the Democratic primary vote.Since October, there have been at least ten widely publicized announcements of more than $130 million in grants to the city, including a number of special allocations granted to only a few cities in the country.

Yesterday's briefing was the second for Maryland leaders in the past two weeks. At last week's meeting -- and at an earlier one six months ago -- President Carter put in an appearance.

"It was well worth the trip," said Lem Kirk, a car dealer from Hancock who went to last week's meeting before resuming his duties as Carter's campaign co-chairman in Washington county. "It made me think that those economic problems are in good hands."

Besides those gatherings, Carter last week also invited the editorial editors of both the Baltimore Sunpapers and the Baltimore News American to the White House for audiences. The Sunpapers subsequently endorsed him.

Sen. Edward Kennedy's campaign chief in Maryland, Rep. Barbara Mikulsi, does not look as favorably on the issues briefings. "I think everyone in Maryland has a right to know the president's positions on the issues, not just those select few invited to the White House," she declares to supporters.

Whatever they may say, however, Kennedy's supporters cannot match a trip to the White House -- nor dissuade many local politicians from going.

Kennedy's campaign has also had no way of matching the series of Baltimore press conferences over the past few months where Mayor William D. Schaefer, a vocal Carter supporter, has happily announced another does of federal bucks for his city.

Last Dec. 21, for example, Schaefer declared that he had just received "a call from the White House" promising the city $1 million for the renovation of two parks.

Two weeks later, Baltimore won $100 million from the federal Department of Transportation's unused "discretionary" funds for its $400 million project to build a highway tunnel under the city's harbor.

On April 7, the day the Carter headquarters opened in Baltimore, Schaefer told reporters that Carter had decided to award Baltimore $7.3 million in special urban development grants. "We are extremely grateful to the president," Schaefer said.

And most recently, Schaefer held a press conference Wednesday, six days before the primary, to announce another Carter administration grant to the city's Fort Holabird Industrial Park -- this one for $4.3 million.

"this is an example of what the president can do," the mayor exclaimed.

Schaefer clearly resents the charge that Baltimore's political support, like that of other major primary cities, has been bought with federal largesse. l"I would never consider something like that," he said. "When a man has done so much for your town in its hour of need, you don't turn on him and ask for more when he needs you. I support Carter because I respect the man."

On the other hand, Carter supporters clearly wouldn't mind if Maryland voters got the idea -- rightly or wrongly -- that Baltimore is the favored town of the Carter administration.

"This administration has delivered to the cities," said Vice President Walter Mondale when he visited Baltimore last week. "Just to make sure we put Bob Embry (Baltimore's former housing administrator) in (as assistant secretary of the Department of Housing and Urban Development) to make sure that Baltimore got more than its share."

And at least one potentially important Kennedy supporter -- Baltimore City Council President Walter Orlinsky -- was persuaded after a White House meeting two months ago that he should stay out of the campaign if his pet project, a regional solid waste authority, was to receive federal grants.

Orlinsky, Schaefer, Baltimore County Executive Donald Hutchinson, and Lieutenant Gov. Samuel Bogley, among others, visited presidential aide Jack Watson to spur his interest in the proposed local authority, which, they said, could use federal aide to get off the ground.

No commitments were made at the meeting, Schaefer and Hutchinson said. However, Orlinsky, who expressed an early interest in working for Kennedy, soon afterward told Hutchinson and others that for the sake of the solid waste authority, he was staying out of the campaign.

Two weeks ago, Orlinsky departed for Israel, scheduling his return for two days after the election. "That," remarked one way Kennedy supporter, "was probably the longest 'walk' in Maryland political history."

Schaefer denies the visit to the White House had anything to do with politics.

"Orlinsky has a habit of saying things like that," he said. "We went to see Watson because he's a friend of mine. I wouldn't have arranged the meeting if I thought it amounted to political pressures."

Mimi DiPietro, the 75-year-old ward boss of East Baltimore, similarly discounted his several invitations to the White House -- and Carter's trip to his neighborhood last August -- as strong influences on him.

"I could say that I'm supporting the president because he invited me to the White House," DiPietro said. "I could say I'm doing it because he invited me out with him onto that balcony (in Little Italy last August), or because he asked me, a big dumb bassett, to sit next to the First Lady at dinner.

"I could say that's why I support him, but that's not the reason. I'm for him because he's given a hell of a lot of money to Baltimore."