Marvin Mandel, backed by a generation of political figures who dominated the government of Maryland for decades, returned to the State House yesterday evening for an event many of those present called long overdue.

Mr. Mandel, 73, the convicted, imprisoned, pardoned and legally exonerated former governor, sat quietly by, a look of melancholy playing across his features, as his portrait was finally hung in a place of honor, along with the portraits of most of his predecessors.

He brightened considerably when his turn came to speak. "All of the people here have in someway or other played a role in my life, and all of it in a good way," he said. "It's something you can't express in words, you can only express it in the way you feel".

The former governor's portrait now resides between his predecessor once removed, J. Millard Tawes, and his successor, Harry Hughes, who claimed the office with an upset win in the 1978 Democratic primary after a campaign in which the alleged corruption of the Mandel years was a major issue.

Absent is a portrait of the man who preceded Mr. Mandel as the state's chief executive, Spiro T. Agnew, who resigned the vice presidency of the United States 20 years ago last Sunday under pressure from federal prosecutors probing kickback allegations against him. When Mr. Hughes was governor, he had Mr. Agnew's portrait removed.

The Mandel canvas, painted by Southern Maryland artist Peter E. Egeli, shows the former governor looking dignified and in charge, his pencil poised over House Bill 851 of 1971. That measure established the state's Public School Construction Program, legislation that Comptroller Louis L. Goldstein, in a tribute to Mr. Mandel, called "a lasting legacy to the state of Maryland."

The gathering in the Governor's Reception Room, where the portrait was unveiled, resembled a tableau of the powerful and well-connected of a generation ago, though some still wield considerable influence today, publicly and behind the scenes.

Power brokers

There were power brokers like former state Sen. Roy N. Staten, a former state Democratic Party chairman, and West Baltimore's William "Little Willie" Adams; retired lobbyists like George W. Gephart of the Baltimore Gas & Electric Co. and James Doyle, a contemporary of Mr. Gephart but still very much active on behalf of clients.

There were also members of the judiciary, among them Chief Judge Robert C. Murphy of the Maryland Court of Appeals, named to his post by Mr. Mandel, and Chief Judge Alan M. Wilner of the Court of Special Appeals, a former Mandel aide.

Even one of his former state police bodyguards was at the unveiling, Col. Larry W. Tolliver, now superintendent of the Maryland State Police.

Mr. Gephart said of Mr. Mandel, "He was rock solid. When he gave you his word, his word was his bond. As far as I'm concerned, this put an end to a long, sad chapter in Maryland history. It's over as of tonight."

Of the former governor's long legal saga, Henry Rosenberg, the Crown Oil Co. chief executive, said, "It's a shame those things happen, but that's yesterday's news. Everybody in their careers makes a misstep, but he recovered and conducted himself very admirably over the years."

'A great man'

Gov. William Donald Schaefer, in accepting the portrait on behalf of the state, said, "He was a true friend, a great man. I have great respect for him, and I will till the day I leave this earth."

No public funds were used for the portrait, which cost $24,000. Bruce C. Bereano, an Annapolis lobbyist and close friend of Mr. Mandel, raised the money from private sources, including many of those in attendance last night.

Mr. Bereano said he hopes to solicit an additional $3,000 to $5,000 to cover remaining costs associated with the painting and its unveiling, including a private reception in the Governor's Mansion that followed the ceremony.

Mr. Mandel was convicted of mail fraud and racketeering 16 years ago, while in his second full term as governor.

In 1981, while Mr. Mandel was in federal prison, Mr. Bereano spearheaded a drive that resulted in President Ronald Reagan granting Mr. Mandel clemency. In 1989, a U.S. Supreme Court decision reversed his conviction.

Mr. Mandel's license to practice law has since been restored. He has become a lobbyist and he remains a popular figure, along with his wife, Jeanne, on the Annapolis scene.