Why all the fuss about Jimmy Caeter's assertion that Ramsey Clark should be prosecuted for visiting Iran? The comment, after all, only rubs in deeper a point the meanest intelligence must surely have grasped long ago.

Mainly that at every turn of the Iranian crisis -- in big things and in small, in matters of life and of death, in military, diplomatic and economic affairs -- Carter's actions have at all times been ruled by a single, dominant consideration. That consideration is domestic political advantage.

Start with the seizure of the hostages last November. It quickly became evident that the best American response was to isolate Iran, keeping open all options but refusing any dealings anywhere until release of the hostages.

At that time, however, Carter felt the need to show he was a leader, resolute, compassionate and calm. So he moved to do everything all at once. He lit candles and dimmed Christmas trees. He renounced the use of force. He cut off oil purchases and froze assets.

He went to the World Court, and the Security Council and the General Assembly of the United Nations. He even dispatched a mission to Tehran under, of all people, Ramsey Clark. In the process, he made release of the hostages seem to be the supreme object of American foreign policy, morning, noon and night, all over the world.

When the Russians invaded Afghanistan, Carter was perforce obliged to do much more. He declared the country was now confronted with "the most serious threat to peace since World War II." Stern measures were required, and the president himself proclaimed -- in terms reminiscent of past presidents in fine hours -- a Carter Doctrine for the Persian Gulf.

As foreign policy, the Carter Doctrine had almost no operational significance. But the atmosphere of crisis produced one domestic action of undoubted consequence. Carter, pleading the press of national security business, ducked the debates he had previously agreed to hold with Sen. Kennedy.

In support of that decision the White House leaked an internal memorandum that purported to show that all of the president's political advisers favored his participation in the debate. Attached to the memorandum was a handwritten note by Carter. In it, he said: "I can't disagree with any of this, but I cannot break from my duties here which . . . only I can fulfill . . . Iran and Afghanistan both look bad and will need my constant attention."

Now it develops that memorandum was prepared and leaked by press secretary Jody Powell. Several White House political advisers have told Martin Schram of The Washington Post that they believed skipping the debates was excellent politics. There is even some evidence -- including a comment by the campaign manager, Robert Strauss -- that the president's handwritten note was custom-tailored for the purpose of buttressing the bogus claim advanced by the leak.

Having donned the hat of commander-in-chief, having threatened sanctions and opened an option to use force, Carter could not suddenly go limp. It was in those circumstances that he ordered up the rescue mission. While many aspects of that affair remain in doubt, the wrath Carter subsequently vented on former secretary of State Cyrus Vance shows plainly what happened.

The raid was ordered by the president for political reasons. Defense Secretary Harold Brown and the Joint Chiefs went along as good soldiers without any serious assessment of the plan. Hence the mounting of an operation so deficient in concept and detail that we are all lucky it aborted early.

Vance, and Vance alone, opposed the raid because he was looking for an issue on which to resign. The president took the Vance position as a mark of disloyalty to a political decision. Hence his dumping on the former secretary.

In the aftermath of the raid, the president announced that he could come out of the White Houe for political purposes becaue matters were now "more manageable." Naive people were dumbfounded. They knew that, if anything, Iran, Afghanistan and various troubles in the Mideast and with the allies had become worse. They forgot that there was one problem that had indeed become "more manageable." That was the problem Carter had been eyeing all along -- the problem of whipping Kennedy in the primaries.

Coming after that veritable Ninth Symphony of crisis politics, the Clark affair is the merest coda. Of course the president had no business commenting in public about a possible court action. Of course he was woefully misinformed about the strength of such a case. Of course he delayed comment until after it was clear Clark was not going to help the hostages.

But all that is beside the point. The point is that Clark is now an object of public dislike and obloquy. So despite his original confidence in Clark, Carter sacrifices all the normal rules of decent behavior to follow the one principle that has always ranked highest with him -- the principle of short-term political gain.