In a small meeting room of a downtown hotel, a group of Maryland Republicans today made official what has been an open secret around the state for weeks as they announced their plans to try to draft former Iranian hostage L. Bruce Laingen as a candidate for the U.S. Senate.

"We think Bruce Laingen has all the qualities one could want in a U.S. senator," said George S. Wills, one of three chairmen on the 30-member "Draft Bruce Laingen for the U.S. Senate" committee. "He has been tested under the most difficult of circumstances in the past and he has met those tests."

Running for the Senate in Maryland against incumbent Democrat Paul S. Sarbanes would be a test for any Republican because of the state's three-to-one Democrat-Republican registered voter ratio. But many state Republicans think Laingen, who was charge d'affaires of the Iranian Embassy and the ranking U.S. hostage during the 444-day crisis, would have a bipartisan appeal that the two candidates already in the race, Lawrence J. Hogan, the Prince George's county executive, and V. Dallas Merrell, a Montgomery County businessman, lack.

Another co-chairman is Alonzo Decker, honorary chairman of the board of Black and Decker Inc. "I have nothing against the other candidates," said Decker, who in the past has supported former senator J. Glenn Beall, another man who is considering entering the race. "But I think this man (whom Decker has never met) is clearly head and shoulders above the other candidates, and that's why I am supporting him."

The group hopes to raise enough money to convince Laingen, 59, of Bethesda, to announce within the next four to six weeks. Laingen, who is vice president of the National War College at Fort McNair, would have to leave federal employment before announcing his candidacy.

"I liken this situation to 1952 when Dwight Eisenhower was a national hero and was convinced he should run for president by a grass-roots citizens group," Wills said.

Laingen, who has steadfastly refused either to commit to or pull out of the race, was out of town yesterday and could not be reached for comment. Many state Republicans view his registration last month as a Republican (he was an independent in Minnesota previously) and his recent speaking appearances around Maryland as signs that he is serious about the race.

Wills said he became convinced that forming the committee was worthwhile after a lunch on Dec. 23 attended by Laingen, Jeannette Wessel, the state party treasurer, and Charles W. Mitchell, another member of the committee.

Many of the committee members are part of the Baltimore business community. Another member is Charles Baldwin, former ambassador to Malaysia, who said he had never met Laingen but would like to see more Foreign Service officers use their international experience in the Senate. Baldwin is one of 20 members of the committee who have never met Laingen.

Allan C. Levey, the state party chairman, noted, "We think Sarbanes is vulnerable and some people think Laingen is the man to beat him. I think some people may hold off on contributing to another candidate until they see what Laingen is going to do. And I think Bruce is waiting to see how well this committee is received around the state."