He has held public office in Maryland for more than half of his 59 years, eight of them in the state's top job. He can command, on short notice, five minutes of precious air time in one of the nation's most expensive television markets. And at his disposal is a full-time staff devoted exclusively to shaping his public image.

Yet as Harry Roe Hughes comes to the end of his second and final term as governor of Maryland, he insists that the public "doesn't really know" him or the true story of his administration's accomplishments.

Now, as Hughes embarks on a campaign to become Maryland's next U.S. senator, advertising his administration's record is his top priority before the September Democratic primary.

"My case is 30 years in public office in various capacities," Hughes said in an interview in his Annapolis office last week. "In this job you see what happens when you make a large cut in Medicaid. I don't know whether everybody over there [in Washington] has that perspective."

The campaign begins in earnest today with a $100- and $250-per-plate "salute" to Hughes' three decades in public office, which interim campaign manager Paul Bograd estimated will bring 1,000 people and "a couple of hundred thousand" dollars in campaign funds.

The irony is that, even after 31 years in public life, Hughes needs all the attention and support he can get. He is entering the crowded Democratic primary field as an underdog, trailing in every major statewide poll behind Rep. Barbara A. Mikulski (D-Baltimore). Bruised by the lingering savings and loan crisis, which sapped his energies and eroded his popularity, Hughes finds himself in an unexpectedly tough fight for his political life.

It is an unusual position for an incumbent governor to be in, especially Hughes, who was elected in 1978 by the greatest margin of victory for any Maryland gubernatorial contender this century, and who was reelected four years later by an overwhelming 62 percent of the voters.

But the current circumstances are fully in keeping with a man whose political history has been marked by a series of come-from-behind successes -- even as recently as the legislative session that ended Monday night.

"I think the governor has been a good governor, far better than his critics would have you believe," said Attorney General Stephen H. Sachs, who was elected at the same time as Hughes and now hopes to succeed him.

"He has not been a good politician in many ways. He has not always gotten the credit he deserves . . . . The perception lingered far too long that the legislature was running the show and the public didn't have the kind of guiding star they were looking for."

Sachs' point was illustrated this year, when the General Assembly convened its regular session in January in an uproar about the crisis in the state's thrift industry.

Though Hughes had succeeded in resolving a portion of the thrift problem, stanching depositors' runs on savings and loans and selling off one troubled thrift, he had missed several of his own deadlines for revealing plans to resolve the crisis. Depositors highlighted their distress during a rally on opening day of the session. "Heave-Ho Harry-O, Out of Politics You Go," one sign said.

Hughes, by all political odds, was in for his roughest tumble ever with the often bullying 188-member legislature.

Already the butt of legislators' jokes, Hughes incensed delegates and senators even more when, a week after the opening of the session, he delivered a lighthearted annual State of the State address that made no mention of the thrift crisis and created a handful of new programs, including a $38.7 million housing proposal.

But when the 90-day session ended, Hughes, as he has done at critical points in the past, emerged having neutralized some of his earlier critics. A Baltimore circuit judge had approved his repayment plan for depositors of Old Court Savings & Loan, where the run began last May. A second problem thrift was sold last month.

Lawmakers had approved new regulations designed to ensure that a similar problem would not happen again. And the General Assembly had adopted Hughes' budget virtually intact, including new spending programs for education, housing, family planning and nutrition.

Though some lawmakers said Hughes' legislative proposals were designed to avoid an election-year controversy -- the housing initiative, for example, was funded largely with money redirected from other programs -- others came away from the session pleased.

"This puts me in a difficult position . . . but what can I say? I think he's done a good job. I think his appointments have been excellent," said Senate Minority Leader John Cade (R-Anne Arundel).

Republican Sen. Howard Denis of Montgomery County, who has been critical of Hughes' performance in the past, said: "He's coming out of this session much stronger than when he went in."

In some ways, that has been the story of Hughes' relationship with the political establishment. In his first campaign for governor, he was derided by one Baltimore senator as a "lost ball in high grass." But then he went on to an upset victory over former acting governor Blair Lee III and Baltimore County Executive Ted Venetoulis.

In the 1982 election, his standing again was viewed as rocky after a couple of stormy sessions with the legislature. He dramatically revived his fortunes, however, after opening the legislative session with a traditional Democratic barn-raiser attacking President Reagan's budget cuts and ending it by pushing through a controversial gasoline tax increase to replenish the state's transportation trust fund.

Through both of his terms in office, he has won high marks for rewarding merit rather than political connections in making appointments to coveted patronage jobs. The same is true for his implementation of an array of new programs, including measures to clean up the Chesapeake Bay, increase education spending, upgrade welfare grants, and extend state involvement in areas such as shelters for battered women and the homeless.

Despite his successful political turnarounds, his critics say he has not demonstrated the initiative, the vision or the political savvy to make him a great leader. "He does not sit around and look from the bay to Oakland and say, this is where Maryland ought to be in 10 years," said Del. Timothy F. Maloney (D-Prince George's), once one of Hughes' sharpest critics. "He looks at what's on his desk and takes it on its merits. What initiatives you've had are things that have filtered up."

Although Hughes' supporters, particularly his staff, reject this view, his campaign for Senate is clearly aimed at changing the perception of the governor as a timid leader. Tonight's fund-raiser saluting Hughes' career has been carefully orchestrated to get the public to begin linking Hughes' name with the most visible successes of his stewardship.

Hughes' campaign managers believe he can blunt negative opinions of his performance if someone explains to voters why he took certain actions, particularly on the thrift crisis, which Hughes himself has called "a public relations disaster." Using the findings of "focus groups" -- small groups of voters used to test out theories of how to shape public opinion -- Hughes' campaign managers discovered that the governor wins support of voters who associate him with programs such as the Chesapeake Bay cleanup and funding increases for education.

The campaign's success at altering Hughes' image and making him better known to voters is critical to his success, particularly since he carries the highest negative rating of the four Democratic Senate contenders, according to a recent Washington Post poll.

Hughes' negative image is a result of "misperception, misinformation or lack of information," said Hughes' wife Patricia, an active force in his campaigns. "The campaign will correct this because the governor will go to the people with the truth, and the truth will prevail."