With classic Baltimore clubhouse pols joining button-down liberals from Montgomery County and members of every political persuasion in between Maryland Gov. Harry Hughes and much of the state's Democratic establishment came together today to endorse the reelection of President Carter.

Finally making his well-known presidential preference official, Hughes announced at a carefully orchestrated press conference that he would serve as honorary chairman of Carter's primary campaign in the state. Nearly 100 state politicians joined him for the announcement.

"The reelection of President Carter will ensure the continuance of the tone of moderation and civility in our public life," Hughes told the gathering at the Annapolis Hilton.

Hughes praised the president for his "calm and quiet strength in the Iranian situation" and for the establishment of what he called "excellent" federal-state cooperation from which Maryland has "benefited immeasurably."

As has been the case in various states around the country, the "benefits" Maryland enjoys from that cooperation have become more evident as the election draws nearer. Today, for example, as Hughes and his Democratic colleagues endorsed Carter here, federal officials in Washington revealed they had approved a $100 million grant to the state for the construction of the Fort McHenry tunnel on Interstate 95, a project long sought in east Baltimore.

Amid all the politicians pumping up the president stood one lone figure sporting a "Kennedy' button -- James Flug, the Maryland coordinator for Sen. Edward M. Kennedy.

"They said they were having a public meeting here, and I just thought I'd come around," Flug told reporters as the press conference ended.

"No class at all," was presidential aide Arnie Miller's comment on Flug's unexpected appearance. But Flug carried on, attempting to minimize the impact of the flood of Carter support.

Flug and Kennedy campaign chief Stephen Smith were in Baltimore Wednesday wooing one of the few prominent Maryland politicians not in the Carter fold -- Attorney General Stephen Sachs. But today Sachs said. "It was a nice chat. Smith's a very charming guy . . . but I'm still firmly in the middle."

While Smith and Flug were pursuing Sachs, state Senate President James Clark, an early Carter supporter in 1976, was phoning his Senate colleagues for the president, and Del. Paul Weisengoff, a Baltimore politician known for his powers of persuasion, was brandishing a list of House members he said he had signed up for the Carter team.

Today, at the Annapolis Hilton, Miller, who is the White House personnel chief, was chatting with former Gov. Blair Lee III about details of a part-time job on a federal commission, one of various federal jobs Lee has been offered in the last year.

In fact Lee, an early Carter supporter last fall, had been pursued all the way to a camping area in the Virgin Islands by a White House minion anxious to talk with him about the job.

Lee was sought out on a jungle path by a surprised ranger, who said there was a call for him from the White House. But when Lee asked to use the campground phone -- the only one within miles -- he was told "it was against regulations" Lee finally got through after finding a phone miles away. He still hasn't decided if he'll take the job.