Pity the poor Peace Corps. Like the celebrated little steam engine that could, it has chugged along in its own unassuming way for two decades, under five presidents. In the face of assorted bureaucratic and budgetary vicissitudes, it has done its uniquely effective thing with extraordinary bipartisan support.

Now, suddenly, it is caught up in a senseless congressional confirmation battle -- senseless because the solution is simplicity itself. The solution is to give back to the Peace Crops the administrative autonomy that was so much the key to its integrity.

Taking it a step at a time, the root of the current controversy lies in an early decision by the Nixon administration -- for reasons that had little to do with anything other than the familiar impulse of new presidents to put their own stamp on things -- to create a new agency, Action, to oversee volunteer programs at home and abroad. Thus the Peace Corps (which had been operating with a direct line through the secretary of state to the president) and its domestic counterpart, Vista, came under one roof.

Thus was the stage set for a protracted argument in recent weeks over the administration's choice of Thomas W. Pauken, an Army intelligence officer in the Vietnam War, as head of Action. In other respects, Pauken's credentials -- a Young Republican, a conservative Texas lawyer and politician, a member of the National Advisory Council on Vocational Rehabilitation -- would seem to be in order. a

But the intelligence background is a sticking point. Peace Corps Regulation 643 quite explicitly bars from service anybody with an intelligence connection within at least the past 10 years.

Now, there are more than a few close questions involved here, having to do with the actual dates of Pauken's intelligence service, the nature of it (how "convert" or "clandestine" it actually was) and the limited authority that Action exercises over the Peace Corps. (There is even some question of how candid he was in his testimony.)

None of these questions is likely to get in the way of Senate confirmation of Pauken in a vote scheduled for today. But there the matter most definitely will not end. The crucial next step will be an effort, already launched by Sen. Alan Cranston (D-Calif.) and backed by others, to resolve the matter once and for all by removing the Peace Corps from Action and reestablishing original autonomy.

This, coupled with Pauken's confirmation, would serve at least two useful purposes. It would put an end to the irrelevant claim by some that the campaign against Pauken somehow had something to do with his Vietnam service -- that this in itself was somehow disqualifying for a Peace Corps manager.

More important, it would address the real issue, which is the integrity of the Peace Corps -- an issue that Pauken himself does not seem to understand.Emphatically, he refuses to acknowledge that, even giving him all the best of the argument, his appointment would raise a problem of appearances. He does not seem to grasp, in other words, to what extent the appearance of even the slightest intelligence involvement has been a threat to the Peace Corps, as a very practical matter, from the beginning.

Sargent Shriver, the corps' first director under President Kennedy, flatly asserts that Pauken could not qualify as a volunteer by his reading of the regulations -- but is not even sure the point's worth arguing. The point he would argue is that Pauken, if even nominally responsible for the Peace Corps, would needlessly give the Soviets a made-to-order propaganda weapon.

"The Soviets attacked us from the first day as an intelligence operation," Shriver recalls. He also remembers that the CIA, which has traditionally used a variety of government agencies as "cover" for its personnel, was quick to cast covetous eyes on the Peace Corps. According to Shriver, President Kennedy personally instructed his national security adviser, McGeorge Bundy, to order a "hands-off policy" by the CIA and to see that it was "policed."

Shriver concedes that the Soviets are free enough, without any evidence, to go on accusing the Peace Corps of intelligence activity; to prompt Third World governments to expel or refuse to accept Peace Corps missions; even to incite violence against corps personnel working in remote areas with scant security. But that, he insists, is no reason to "make it easy for them by providing the grist for their propaganda purposes."

That, of course, is exactly what the controversy over the Pauken nomination has done; in the hearings, the debate and subsequent press disclosures, his intelligence connections have been explored and laid bare. The only way to undo the damage to the Peace Corps -- if Pauken is to head Action -- is to break the Peace Corps' connection to Action by restoring its autonomy.