Lifting his pinafore above the muck and clinging to cliche's as to a lifeline, the committee counsel undertook to instruct Oliver North: communists deceive, so we should not, so covert operations are un-American. The gate having swung open on a child's garden of moralisms, North eagerly came out to romp on his preferred ground of passionate belief. He replied that the world is dangerous.

Thus were the issues joined between a litigator and a lieutenant colonel. The nation still was not hearing, on either side, from the kind of people who should be in charge of political debate: politicians.

In descending order of importance, the three reasons for having these hearings are: to clarify the president's role, to elucidate the procedures that produced the blunders, and to assemble evidence of lawbreaking. The first reason is most important because it concerns the political vitality of the government's central energizing institution. The second reason is public pedagogy, a legitimate use of legislative hearings. The third reason is relatively trivial, and may turn on such technical questions as whether the profits from weapon sales were U.S. government assets.

But the third reason seems disproportionately important because of the role played by the committee's hired litigators, John W. Nields Jr. and Arthur L. Liman. They resemble very strong bloodhounds at the end of a very long leash held by a very small boy.

The questions that make these hearings deserving of the description ''historic'' are political questions. They concern the distinctive functions of the government's branches, the different ethics of public and private actions, the compatibility of democracy and secrecy.

But for days, the political people -- the members of the committee -- were mere props, utterly passive as two litigators set the tone and miniaturized the controversy. There is nice irony in the fact -- and some members of the committee acknowledge that it is a fact -- that Congress, whose expanding desire to control foreign policy is at issue in these hearings, has not quite controlled the hearings.

It is clear that, a senator on the committee says, North was not Metternich, he was Sergeant York. It was Reagan administration policy to get weapons to Iran and aid to the contras. North's assignment was to get those jobs done. The Metternichs are still missing from the jigsaw puzzle. One of them, CIA Director William Casey, is dead.

Although Casey talked like a man chewing Grape-Nuts, he was brave, brilliant and foxy. He would have been an instructive and perhaps emblematic witness. He brought to the necessary business of covert operations a buccaneering spirit. He may also have brought a, shall we say, casualness about the process. Such casualness may be the contribution of conservatism to this mess.

Deep down (when there is a deep down), many conservatives do not like government, so respect for its institutions does not act as a flywheel on their moral motors. They lack the patience enjoined by politics based on public and private persuasion.

In one of his plays, Tom Stoppard writes: ''Skill without imagination is craftsmanship and gives us many useful objects such as wickerwork picnic baskets. Imagination without skill gives us modern art.'' Modern art, and foreign policies such as arms sales to Iran. Where were the senior conservatives in whom skill and imagination are supposed to be joined?

It has been said, with government in mind, that the best carriage horses are those that can most steadily hold back a carriage as it trundles downhill. Where were those horses, the most seasoned officers -- secretaries Weinberger and Shultz -- when the administration headed downhill?

It is difficult to be definitive about the ethics of dissent in government's inner councils, but surely those two men, and especially Shultz, should have stopped policies they considered dangerous, or should have closely controlled them precisely because they considered them dangerous, or should have resigned.

A friend once said to Al Smith, ''To tell you the truth, Al, this election campaign has not helped me to make up my mind.'' Smith replied, ''To tell you the truth, Charlie, if you need an election campaign to make up your mind, you must be a dumb sonofabitch.'' So must anyone be who needs hearings to make up his mind about the folly of arming a terrorist regime while the secretary of state lectured allies against doing that.

Finally, a cautionary note. It has been said that when there are conflicting versions of a story, it is wise to believe the one in which people appear most disreputable. That was unwise concerning North and probably is concerning his superiors. That needs to be emphasized because of liberalism's contribution to the current climate: the attempt to criminalize policy differences.