Secretary of State George Shultz having come and gone from the Iran-contra hearings, we have heard now from the main players, and two questions crowd the mind.

Adm. John Poindexter told the investigating committee that he had not informed the president that he was diverting funds realized from the sale of arms to Iran because he did not wish to encumber the president with knowledge of something that might be conceived of as an irregularity. He also said he had no reservations about putting the money to that use because he was certain that such an act would have been approved of by President Reagan.

Whereupon we heard from the White House the one truly sour note of the entire investigation. A spokesman for Reagan said: Not at all. The president not only didn't know about the diversion of funds (that we all knew), but the president would not have permitted that diversion had he been asked about it.

That is the most damaging statement President Reagan could have made because it confirms the charge of his critics that Reagan was not in charge of the policies being made in his name. Earlier, Reagan was damaged by the Tower Commission, which found the president generally uninformed. ''At no time,'' the report said, ''did he insist upon accountability and performance review. . . . Setting priorities is not enough when it comes to sensitive and risky initiatives that directly affect U.S. national security.''

What the president has done is in effect to corroborate the charges by his critics of ill management. And the awful suspicion arises that he was induced to say what he did by advisers who gave insufficient thought to its implications. After all, given that Reagan did not know about the fund diversion, he has been free to make up his mind about its retroactive justification. And it is possible that what he would have agreed to do in the fall of 1985 he would not, in the summer of 1987, have agreed to go along with. We know from earlier statements that Reagan believes that he made a wrong decision in agreeing in effect to swap arms for hostages. By the same token he may, in retrospect, have come to the conclusion that the fund diversion was politically excluded.

How much better it would have been if the president had said: ''If the proposal had been made to me, I would have consulted my legal counselor. If he thought the diversion within my powers, I'd certainly have approved the use of the funds to keep the contra movement alive pending Congress' refinancing of it.'' Not only would such a statement have been consistent with Reagan's general behavior -- after all, he was willing to receive in the Oval Office foreign officials who had contributed money to the contras and to thank them for doing so; it also would have fortified Poindexter.

It is always useful to a president to have the opportunity to demonstrate to Congress and the American people why he chose to appoint the men he selects to serve him. Poindexter said he was certain that Reagan would have endorsed the fund diversion, and it transpires that Reagan would have done no such thing. The result? Poindexter's competence is severely challenged, and one wonders why the president trusted an untrustworthy official.

A second anomaly is the posthumous portrait we are asked to accept of William Casey. Shultz urged Congress to believe that Casey was obsessed by his concern for the hostages, so much so that he was willing to conspire to release the terrorists in Kuwait in return for them.

Now this is, quite simply, very hard to believe. Casey was a hard-boiled gentleman who was conversant with the practices of a hard-boiled profession (espionage and counterespionage). The CIA is one of those life styles in which you can find yourself carrying cyanide in your mouth in case of failure. In case of failure you do not expect that foreign policy will be changed to the advantage of the enemy. If the enemy was thus lightly to be regarded, there was hardly any point in risking life and limb in the first instance to do that enemy damage.

No, William Casey was not, believably, the sentimentalist willing to risk everything in return for an American hostage. And Ronald Reagan is not believably the man who would have recoiled at a financial maneuver that served an important plank in his foreign policy -- nor, believably, the kind of man who would engage in a position of critical power an admiral who would misread the presidential mind on so important a point.