Harry Roe Hughes was sworn-in as Maryland's 57th governor today with a promise to restore pride and integrity to a state that "has had enough political manipulation, enough unfulfilled promises, enough scandal, shock and shame."

"I come before you as the governor with the greatest mandate in Maryland history to effect change," said Hughes, 52, who was elected last fall on a political integrity theme after two successive governors -- Spiro T. Agnew and Marvin Mandel -- were implicated in scandals. "I will live up to the electorate's expectations."

Hughes, a quiet progressive from a small town on the Eastern Shore who has built a reputation for honesty in the give-and-take world of Maryland politics, pledged to erase the stain of scandal from the state by making political independence and candor "the hallmark of this administration."

"The highest standard of ethical conduct will begin with the governor and permeate throughout the state service," said Hughes, who resigned as Mandel's secretary of transportation in 1977 to protest the handling of a subway contract -- a resignation interpreted at the time as a form of political suicide.

The deliberate, soft manner displayed by Hughes during his campaign and recent 10-week transition period -- he calls it part of his makeup as a "country boy" -- was underlined in his 15-minute inaugural speech with the words: "I act rather than react."

"We will not be pressured into precipitous action, we will be influenced only by the facts not political or special interest factions or the clamor of media pressures," he asserted. "This is the Hughes style... I will propose comprehensive solutions, I will not govern by crisis.

"To a certain extent, this means Maryland may have a very quiet administration. But I think I can speak for every citizen when I say we've had enough media events. We need meaningful events."

Hughes' ambitious plans for reviving the spirit of Maryland were not matched in intensity by his programatic promises. Instead, he limited his goals this first year to tax relief and reform of the state employe pension system -- two areas, he said, "that require immediate action. Both are imperative to achieve equity in the present and a secure foundation for the future."

"Governor Hughes," a title that had made him "chuckle to myself" the night before, was sworn in at 12:05 p.m. at a brief ceremony in the chambers of the Maryland Senate, where he had served for 12 years. During the swearing-in, he placed his left hand on a Bible passed down from hit maternal grandfather and namesake Harry Roe.

His wife, Pat, and daughters Beth and Ann looked on from front row seats, along with a tightly bunched flock of politicians old and new -- U.S. Senators Charles McC. Mathias and Paul Sarbanes, several congressmen, former governors J. Millard Tawes and Blair Lee III and members of the 1979 General Assembly.

In the gallery of the chambers sat three assistants who had been loyal to Hughes during the primary days last summer when his campaign to become governor seemed hopeless -- Michael Canning, J. Michael McWilliams and Joseph Coale. They made faces at the new governor and tried to make him laugh. "I saw them," said Hughes later. "Believe me, I saw them."

After the traditional ceremony, Hughes, dressed in a rented black morning suit, led a procession out to a sheltered platform on the south lawn of the State House. There, in the cold and damp of this January afternoon, he delivered the inaugural address. Only two of Maryland's four former governors -- Tawes and Lee, the acting governor for most of the last two years -- sat on the platform behind Hughes.

Agnew and Mandel were not invited, and did not attend.

Mandel, who had returned as governor for two days this week after an appeals court in Richmond reversed his political corruption conviction, walked out of the governor's office for the last time shortly before 11 this morning. His departure was as quiet and unnoticed as his return from a 17-month exile had been loud and attention-getting only a few days earlier.

The displaced governor's desire to slip out unseen was thwarted only when the back elevator he wanted to use would not work. "They're so sorry to see us leave," said Mandel, "that they won't even let us out." Once outside, Mandel and his wife, Jeanne, took a look at the hundreds of chairs being set in place for the Hughes inauguration. Beyond the chairs, they saw a marquee sign on the Capital Theater that read: "Goodbye Marvin. Hello Harry."

From the State House, the Mandels repaired to the Annapolis Hilton and sipped champaigne.

At the same time, over at the governor's mansion -- to be referred to from now on by the Hughes administration as "Government House" because Pat Hughes thinks "mansion" sounds "pretentious, ostentatious and tacky" -- Hughes and his family were sitting down for their first meal as the first family of Maryland. State troopers had been keeping reporters and photographers away from the building until Hughes arrived and, in his first demonstration of open government, he said "Come on in."

Throughout the day, Hughes maintained a relaxed style and the humor of the minor league baseball player he once was. He appeared uncomfortable in the elegant morning suit and joked about "doing a little soft-shoe at three o'clock."

While he was waiting to enter the Senate for his swearing in, standing in a crush of reporters and state troopers outside the chamber's heavy mahogany doors, Hughes overheard Senate President James Clark Jr. inside, apologizing for the delay and explaining that the state constitution specifies that newly elected governors take the oath at 12:05 p.m.

"Who has the constitutional watch?" joked Hughes, just moments before becoming chief executive.

The ceremony finally complete, Hughes strolled back into the Senate lounge, where he greeted State Comptroller Louis Goldstein among hundreds of well-wishers.

"Harry, you're on the payroll now," said Goldstein.

"I knew something felt good," replied the new governor.

Across the room, a much smaller crowd surrounded Lee, who became lieutenant governor again after Mandel reclaimed his powers Monday. Bidding farewell to friends and reporters who have known him during the past decade, Lee treated his final ceremonial duty with characteristic good humor.

"I'm getting ready to be the sage of Silver Spring," said Lee, a Montgomery County resident, raising his right hand as if taking an oath after a reporter asked if he was preparing to become an elder statesman.

"I was thinking when (Lt. Gov. Samuel W.) Bogley took the oath," Lee said, "I became an unemployment statistic."

Lee, in his 17 months as acting governor, supported many of the goals proclaimed by Hughes today, such as permitting the legislature the freedom to become "the principal policymaking body of government." But Hughes had little good to say about the past in his first speech as governor, saying "this administration will be different from any that has preceded it."

Hughes, who began his first day as governor with less than half his cabinet positions filled, said his appointments "will be based on professional competence and a common commitment to change. Experience will be valued but so will vision, initiative and altruism. There will be no empire building nor territorial battles."