John Hargreaves, the gruff chairman of the House Appropriations Committee, had tried to tell his panel's members that he wanted to kill a bill extending veterans' preferences to merchant seamen. And so, when a majority of the committee's delegates ignored him and pressed for a favorable vote, he felt obliged to use a blunter approach.

"We're not voting on this now," announced Hargreaves, tucking the bill back into his files as committee members pleaded in vain for a vote. "I'm not sure we know what we're doing."

Under the rules of Maryland's House of Delegates, Hargreaves was perfectly within his rights in defying the will of the committee's majority. For committee chairmen, by virtue of their absolute control of the panel's agenda, can make life-or-death decisions on legislation, particularly near a session's end when delay means death.

Time and again in the past month, several House committee chairmen have used this autocratic power to smother legislation that they don't like.

"There are times when a committee chairman exercising leadership has to use certain procedures that are not democratic," explained House Speaker Benjamin L. Cardin, who appoints the chairmen of the House's six committees.

"I obviously believe that the way a committee should operate is on a democratic, majority-rule concept," Cardin added.

Hargreaves' view of the democratic process is more flexible.

"The [merchant marine] bill was lobbied very hard, very, very hard," Hargreaves said today when asked about his refusal Thursday to allow a favorable vote. "When I saw that happening I said that this game could be played two ways."

A month ago, faced with probable committee approval of a measure allowing an extension of the payback time on state bonds, Hargreaves simply adjourned the committee rather than allowing a vote in favor of the measure.

"I wanted to talk to Mr. Bainum [Montgomery County Del. Stewart Bainum, the bill's sponsor] about it," Hargreaves snapped when asked why he blocked the vote. After some negotiations the two men agreed to withdraw the measure and bring it back next year.

Hargreaves is not alone in his freewheeling use of power. For more than a week recently, Economic Matters Committee Chairman Frederick C. Rummage (D-Prince George's), refused to send to the House floor a bill which had received approval in his committee by a 15-2 vote.

His action, an apparent violation of House rules, came on a bill sponsored by fellow Prince George's Del. Joan Pitkin prohibiting insurance companies from denying coverage to persons exposed to the drug diethylstilbestrol, or DES, which once was widely prescribed for pregnant women and since has been shown to cause cancer in some of their offspring.

Immediately after the vote on March 25, Rummage refused to report the bill to the floor, telling Pitkin he thought it was unnecessary. Last Wednesday, after Pitkin told Rummage he was violating a rule that all committee-approved bills be reported within three days, the chairman finally relented.

According to Pitkin, Rummage hinted broadly that he had delayed the bill in retaliation for her support of an amendment to one of Rummage's pet bills, a measure benefiting Maryland's savings and loan companies. "He didn't say much," said Pitkin. "But there was an inference."

Rummage denied the charge. "I held it up because I was not satisfied that the problem existed in this state," he said. "If I feel I cannot defend a bill on the House floor, I wait until I can get more data on it. I do that a lot of times."

Torrey C. Brown, chairman of the Environmental Matters Committee, had a different reason for failing to bring to a vote a measure he has ardently opposed for years.

"We've already voted on this thing three times," Brown said, when asked why he was holding back on a bill which would require truckers to cover their loads with canvas.

Other committee members, however, say there is another reason for Brown's action: they claim he knows the bill will pass if one more vote is taken.

On Thursday, several committee members, led by a delegate who had voted against an identical measure and since changed his mind, made a motion for a favorable report. Brown ignored them.

"I think the bill is finished here. They won't bring it up for a vote," fumed committee member Steven V. Sklar. "They won't even recognize the motion."

"It doesn't make a difference if the vote would be 23-1 in favor of the bill, if [Brown] doesn't bring it up, it dies," said Del. Gerald W. Winegrad (D-Anne Arundel), whose change of heart on this issue would have helped make the difference between failure and success on the controversial measure.

Even Helen Koss (D-Montgomery) the good-government champion who chairs the House Constitutional and Administrative Law Committee, is not immune from the temptation to be autocratic. When a measure instituting a public financing system for state election seemed to be several votes short of passage, Koss, who favors the measure, decided to hold it up.

Koss' tactics prompted Del. Paul Wisengoff (D-Baltimore City), an old-style vote trading politician who opposes the measure, to express shock that "Montgomery County's greatest white hat has resorted to strongarm tactics."

Koss, hearing of this, responded that the remark was "a great compliment," coming as it did from one of the greatest vote manipulators in the House. Two weeks ago, when a vote was finally taken in committee, the bill was killed.

In another instance, Koss and members of her committee jointly launched an attack on Del. Gerard Devlin's bill for a new access road to the Bowie racetrack, after the Prince George's Democrat was quoted in a local newspaper criticizing the panel as "ineffective." The committee members managed to hold up the bill for several days until Devlin had completed several rounds of frantic apologies.

"Many of these problems could be avoided if communications were better," House Speaker Cardin said yesterday after hearing of several of these cases. "I'm not condoning these examples but I'm not condemning them either."