Those who agree to serve on the ethics committees of the Senate and the House of Representatives are either the most saintly of people or a combination of the Marquis de Sade and Torquemada.

They may do it because it gives them a degree of power over their fellow legislators, and some in Congress do crave power. There also is political benefit in being able to state on your campaign literature that you are a member of the Ethics Committee, thereby creating the illusion that you yourself are deemed ethical. There are some who actually believe their own purity is so unblemished that they are uniquely qualifed to pass judgment on others.There is, from time to time, much publicity attached to the job. This is one of those times, and a nation weary of the dismal tensions of the Persian Gulf and the economy may turn with some relief to the dismal spectacle of public hearings by the Senate Ethics Committee into the question of whether the Keating Five have engaged in improper conduct.

The hearing room was packed with friends of the actors in the unfolding morality play, and with the news media. Ah, yes, this is a media event, conducted under the same avid public gaze that accompanied French royalty to the guillotine and American outlaws to the gallows.

Other than providing a welcome diversion from more painful issues confronting America, the hearings serve no useful purpose nor does the committee conducting them.

No matter how often the members of the committee invoke the words "solemn duty" and "the integrity of this great body," the hearings are political in nature, dealing with political issues and political interpretations of unwritten laws, unknowable regulations and transitory standards.

The committee's special counsel, Robert Bennett, had recommended before the election that charges against Sens. John Glenn, D-Ohio, and John McCain, R-Ariz., be dropped. That would have left the Keating Three, all Democrats (Donald W. Riegle Jr. of Michigan, Dennis DeConcini of Arizona and Alan Cranston of California), and so that idea was rejected on a wholly partisan vote.

The nation and Congress got along without ethics committees for the first 150 years of their existence. Senators and representatives behaved themselves at least as well as they behave now, were held in much higher repute, and Congress functioned infinitely better than it does now.

The five senators all took campaign contributions from Charles Keating, who was trying to avoid federal regulatory action against his troubled Lincoln Savings and Loan Association.

If, in return for those contributions, they acted or agreed to act on his behalf, that constitutes a crime. Public officials have been sent to jail for such offenses since long before there was a Congress.

On the other hand, every senator who had an account in a savings and loan institution had some small degree of conflict of interest when he voted to bail them out, but if they hadn't voted in their own self-interest there wouldn't have been a quorum to do business.

Between those two extremes are an infinite number of gradations of conflict. The ethics committees can't write rules or standards that cover the multitude of situations; they use ambiguous words like "improper conduct" that mean whatever the current political climate calls for.

For those who like to see important people twisting in the wind, or to watch public executions and witch dunkings, it is good political theater.

Otherwise it serves no useful purpose.