The assumptions of Oliver North will probably be shared by history. The Marine lieutenant colonel "assumed" President Reagan had authorized the diversion of funds to the Nicaraguan contras from the sale of arms to Iran. He wrote five memos to Reagan outlining the diversion plan and not once was he told to cease his activities. His assumption was that he was doing what the president wanted. Ollie North's testimony may later be rebutted, but not his logic.

Consider: North had seemed to be a one-man band in arranging the sale of arms to Iran in exchange for hostages, but in fact he was backed by an ensemble of high administration officials. All the time he was doing that, the president and others were lying about administration policy. The president said he would never bargain for American lives. He did. He said we were neutral in the Iran-Iraq war. In effect, we were not. He said no third country (Israel) was involved, but it was, and he ultimately tried to explain it all by saying he was making contact with Iranian moderates. They probably don't exist.

Consider further: The Nicaragua policy was similarly packaged in lies. The president said he wanted to interdict the flow of arms from Nicaragua to El Salvador. He did not; he wanted the Sandinista regime rubbed out. He said he wanted to pressure the Sandinistas into democratic reforms. He could not care less about reforming a regime he loathed and wanted ousted. His aides told Congress the administration was following the letter of the law and not aiding the anti-Sandinista forces. But the law, like the documents in North's office, was shredded. On the sneak, we were waging war.

Ollie North may be a zealot, but he is no fool. He uses the English language with the dexterity of a Washington bureaucrat. He referred to his various operations as "covert" and then explained to the nation that that entailed lying to anyone, including Congress, to protect the operation. It matters not at all that the law covered covert operations, that their necessity is recognized and acknowledged -- that there is a legal way of doing these things. In this case, the law got in the way and so North (and others) went around it. He was accountable to a higher power, the anticommunist cause and the president who espoused it.

North's assumptions -- if they were that -- were hardly fantasies. In at least a general way, the president did approve of what North was up to. Indeed, many people knew what the president himself was up to. In Nicaragua as well as in Congress, many were convinced that nothing could stop Reagan from going for the Sandinistas' jugular. A lifetime of speeches, thousands of after-dinner remarks, testified to Reagan's vivid nightmare of communism. He seemed willing to fight it on its own terms, and he started down the slippery slope of moral equivalence: the end justified the means.

And the law in all its fastidiousness would not matter because, in effect, the president is the law. "When the commander-in-chief of the nation finds it necessary to order employees of the government. . . to do things that would technically break the law, he has to be able to declare it legal for them to do that," Reagan said in 1977. The law, then, was what the president said it was -- a view that seemed to permeate the administration. How else can you explain why so many high-ranking officials -- one CIA director, two national security advisers, a host of CIA agents and maybe some people in the State Department -- covered up the diversion of funds or the end-run around the Boland Amendment? The president was the law.

"There ain't no smoking gun," Reagan said last month. But North smokes like a Saturday Night Special. The gun is his assumptions -- his quite reasonable conclusion that he was doing precisely what the president wanted. Even to this day, his assumptions seem justified. Where is the outrage from Reagan that his policies were being violated? Where is the indignation of a president who would not, even for a good cause, permit the breaking of the law? None of that is present

Before North appeared as a witness, his credibility was already being questioned. He lied often to protect his various operations, and maybe, some suggested, he would lie before the select committee as well. Time and subsequent witnesses will help answer that question. But when North says he proceeded in his activities on the assumption the president approved, no one who knows Ronald Reagan has any cause for doubt.