As a witness, Oliver North came across as the cocky, counterpunching Naval Academy boxing champ. But a subtler and much more insidious strategy underlies the case laid out for his client by coach and counselor Brendan Sullivan. Call it the ''covert defense.''

It explains everything. You have only to buy the basic premise that (a) it's a geopolitical jungle out there and (b) ''covert operations,'' accordingly, are essential to protect the country. In one of his more emotional outbursts, North all but pleaded for public understanding ''that this is a dangerous world.''

And that is justification enough, he is asking us to believe, for a certain jungle lawlessness: for cold contempt for a congressional hand in policy making, for snappy salutes by underlings in unquestioning acceptance of even the most dubious orders from above; for shredding (or altering) telltale documents; for automatic assumptions of presidential authority at work; for lying ("by their very nature, covert operations are a lie").

Who knows? The ''covert defense'' just might work for Oliver North with a sympathetic public. After all, when he swears he ''never carried out a single act'' without authority ''from his superiors,'' he is simply passing the buck to John Poindexter, who has nowhere to pass it except to the president. That's life in the jungle world of Oliver North.

The immediate question, then, is how well the ''covert defense'' will work -- in any final reckoning of responsibility for the Iran-contra fiasco -- as it works its way up to the top. Awkwardly, I would guess, and ambiguously, which brings us to a far larger point about what we are witnessing. It is not just a case history of bad policy, botched operations, incompetent operatives, abuses of power or the ''privatization'' of foreign policy. We've seen all that in one way or another before.

The larger question raised by Oliver North's ''covert defense'' for the long haul has not as much to do with malpractices of the moment as with principles. It is a question that has been with us for almost all of the 40-or-so years since Congress first authorized the use of ''unvouchered'' public funds for what came to be called ''covert operations'' -- almost any form of undercover, underhanded proxy warfare or political subversion, from bribery to gun-running to assassination.

One crisis has led to another, including the stunning disclosures in congressional investigations of the CIA in the mid-1970s. What the current joint congressional hearings tell us is that we have learned next to nothing -- that we still don't know what, as a matter of sound government practice, is permissible and what is beyond the bounds, or even whether, in an open society, ''dirty tricks'' are do-able.

In the good/bad old days (depending on your point of view), there was at least some common ground. The Cold War was an accepted justification. And Congress delegated discreet oversight to an elite leadership group; for the most part, secrecy was maintained. Then in the rancid post-Vietnam, post-Watergate atmosphere of shattered trust, the whole thing blew up. You can read all the gory details in the findings of the Senate Select Committee chaired by the late Sen. Frank Church.

But it is enough to read that committee's conclusions for a measure of how far we have strayed from what was then accepted, bipartisan wisdom: ''Covert operations'' were by definition those which could not even bear public scrutiny, morally or legally. They were for use when the government's hand could not be allowed to show; there must be ''plausible deniability.'' They should, then, be used sparingly as a last resort under formal, rigid congressional oversight -- with notice in advance.

''Para-military activities'' (contra aid would be a case in point) are an ''anomaly, if not an aberration . . . difficult if not impossible to conceal,'' the Church committee warned. Finally, it insisted, ''covert'' actions must be ''consistent with . . . policies which have emerged from a national debate.''

The mere presence of Oliver North arguing a ''covert defense'' in public congressional hearings is all the dismal proof you need that the Iran-contra transactions, in plain violation of proclaimed U.S. policy and demonstrated congressional intent, meet none of these sensible and elementary tests.