IT WAS a bit odd to hear President Reagan stating last night that there was nothing he could say to make right the situation that grew out of his sale of arms to Iran. There is something presidents can say when things go wrong -- and he certainly said some part of it. No one wants the sort of groveling that abases the man or the office. Mr. Reagan did not do that, and should not have. But almost everyone expects to hear conveyed a sense that the president truly understands what went wrong, has absorbed the implications of it, has absorbed as well the shock and dismay caused by it, and is then prepared to move on.

In his speech on the Iran-contra affair, Mr. Reagan fairly gave himself high marks for cooperating with the various inquiries. He acknowledged that events had been ''confusing and painful'' and had left ''doubts'' in the country. It took some courage to acknowledge that ''I was stubborn in my pursuit of a policy that went astray.'' In that sense it was the right speech. He didn't have to address everything and he could be expected to be more understanding of his own administration's failings than outsiders would be.

Yet it was evident once again that Mr. Reagan's thermostat measuring political outrage, including political outrage that has cost his administration dear, is set low. It is not simply that he did not address some of the more important matters raised in the congressional hearings and that in some he did address -- the origin of the arms sales, for instance -- his presentation went past much that the testimony had revealed.

In saying that his secretaries of defense and state had ''predicted that the American people would immediately assume this whole plan was an arms-for-hostages deal and nothing more,'' he passed over all the sad testimony about their exclusion from the policy circle. In declaring that ''the buck does not stop with Adm. Poindexter,'' he failed to explain or even ask how it was that he too was kept in the dark. He called ''the biggest lesson'' of the hearings the need for executive-legislative trust, as though the two branches were equally at fault for the ''lies, leaks, divisions and mistakes.'' You don't have to believe the congressional record on funding the contras has been constant or a model of legislative precision to know that the main burden of fault clearly falls on the administration. Meanwhile, he ignored that parts of the American government had run operations and made plans that skirted or broke the law.

It was a brisk and brief speech. Mr. Reagan was appearing while he and Congress are on vacation and before Congress issues its own recommendations. He was at pains to cite the steps he has taken to clean up the debris and the broader agenda he still intends to pursue. Still, for all that he tried to put this affair behind him, the main impression he left was that he has not come fully to terms with the most convulsive events his administration has so far known.