Of the many remarkable aspects of Oliver North's performance before the country and Iran-contra committees, here surely is the greatest: North, the quintessential covert operator who labored so long and hard to keep things secret from Congress and hidden from the people, found his greatest weapon in public disclosure.

It was that most public arena, the Congress, that provided the vehicle for the Marine lieutenant colonel to take his case to the entire country, through television, and improve his public standing dramatically.

In North, the president found his most articulate and eloquent advocate -- and again with no little irony, for the president and high administration officials sought for years to keep North's activities secret. Then, when exposed, the public was given lies instead of truth in an attempt to cover up what had, in fact, occurred.

Given North's effectiveness, one wonders whether he and the president might have fared better had they been willing to trust the Congress and the public from the beginning.

The colonel, not the administration, made the best case for the controversial issues that lie at the heart of the affair: the cause of the contras; the need for secrecy in covert operations; the motivations that compel some to skirt the law for what they passionately profess to be a greater good; the reality that makes people like North claim the need to lie to save lives; the elusive but real concept of the "national interest."

For four days North's testimony, and the way he delivered it, produced a sympathetic public response. He seemed to have carried the field in a triumph forged by force of personality, employment of effective rhetoric and tactics -- the Nuremberg defense, following higher orders -- and by presenting a picture of one person battling alone against superior numbers.

For a time, it appeared he had carried the field.

Then, in a most extraordinary way, on his fifth day before the nation, members of the congressional committees began employing North's tactics. Whereas North had appealed over them to the viewing public, this time they directly spoke over his head to the country beyond.

The result was an outpouring of expressions of democratic values. This was no "cave-of-the-winds" kind of political rhetoric common in the hot air of Congress -- as was the case yesterday in the charade over viewing the "Ollie slide show." This was serious exposition of greater public purposes and of the proper workings of the constitutional system, expressed memorably and movingly.

Warren B. Rudman, a Republican senator from conservative New Hampshire and a backer of contra aid, evoked the constitutional phrase, "We the people." He reminded the colonel and the country what these hearings and the issues that prompted them are about when he said: "There is no way you can carry out a consistent policy if we the people disgree with it, because this Congress represents the people." He expressed perhaps the greatest of democratic principles -- the right to differ and disagree -- saying, "The American people have the right to be wrong."

His colleague, Sen. George J. Mitchell (D-Maine), also made that point forcefully when he said that in America, "you can criticize the government without looking over your shoulder."

Mitchell turned one of North's most effective arguments -- that North's views represented the real patriotism -- against him when he said:

"Now, you've talked a lot about patriotism and the love of our country. Most nations derive from a single tribe, a single race. They practice a single religion. Common racial, ethnic, religious heritages are the glue of nationhood for many.

"The United States is different. We have all races, all religions. We have a limited common heritage. The glue of nationhood for us is the American ideal of individual liberty and equal justice. The rule of law is critical in our society. It's the great equalizer, because in America everybody is equal before the law.

"We must never allow the end to justify the means, where the law is concerned, however important and noble an objective. And surely, democracy abroad is important, and is noble. It cannot be achieved at the expense of the rule of law in our country."

Whatever else lies ahead, the Iran-contra hearings have accomplished their central purpose. They have provided what cynics said could not happen: a public forum, held in the most visible arena, in which a genuine debate about basic democratic principles and values has taken place.

Now we'll see what kind of a country we really are.