THE MOST TIRESOME cliche of the political season is the hearty comment that President Carter learns quickly. It's like saying that a pitcher going into the third game of the World Series is showing a knack for picking up the rules of the game. But it leads to a more interesting question: What should he have learned from the rough passages of the past year - and what should Congress and the country have learned?Since it's always helpful to stick to specific cases, let's consider the educational aspects of the major failure of Mr. Carter's first year in office, the unbroken impasse over the energy bill.

In retrospect it clearly seems a mistake to have introduced one gigantic energy bill as the comprehensive solution. Mr. Carter likes comprehensive solutions; his mind inclines toward them. It seemed a good idea at the time, and this newspaper joined in the applause at his courage in taking up all of the energy issues together. That strategy might have worked several years ago, in the initial anxiety over the oil embargo. But the atmosphere has changed. Mr. Carter owes his election to the strong current of public skepticism regarding vast presidential initiatives and, in general, federal claims of competence. Ironically the President is, you might say, the victim of the attitudes that brought him to power.

Because the energy plan started through Congress as one bill, nothing can be settled until everything is settled. Sen Russell Long (D-La.) is holding up the crucial energy taxes until there's an agreement on gas pricing. The House conferees are holding up everything else, including the noncontroversial conservation and utility-rate provisions, until the taxes are worked out. Presumably a bill will eventually be passed, with the usual complicated compromises. At his press conference yesterday, Mr. Carter called it his first priority this year. But it will take effect later than the administration had hoped, and in a greatly diluted form. Will Mr. Carter have another opportunity to get major energy legislation before the 1980 election? Probably not, unless there is some major convulsion threatening the flow of oil from abroad. Having got the bill that he called comprehensive, the President will have great difficulty getting Congress to go back into those trenches. Energy, incidentally, is hardly the only subject in which the passion for comprehensive bills is turning into a political liability. The comprehensive tax-reform bill was to have been introduced in October, but it hasn't appeared and probably never will. The comprehensive welfare-reform bill is now mired down in endless hearings, and its prospects are dim.

The second lesson of the energy debacle - and the more important one - goes to the nature of political leadership. The central reason for the impasse on the bill is that most Americans still don't understand why it is necessary or even useful to do all of those hard and expensive things. Mr. Carter launched the bill last spring with two rain-hail-and-thunder speeches declaring - correctly, in our view - that it was the most urgent business confronting this country. Then he turned to other things and for five months hardly touched the subject. Mr. Carter thinks that virtue and reason speak for themselves. That is a risky assumption for anyone to make, but particularly for a President.

In the fall, he returned to energy with a couple of brief but vehement attacks on the oil companies. Then came a television address that was restrained and conciliatory to the point of being soporific. The effect was apparently to fortify the widespread impression that the crisis must have been the oil companies' fault and that, anyway, it seems to have gotten less compelling. That impression is profoundly wrong, but Mr. Carter has never found a way to explain to voters precisely why it is wrong. When voters do not see the reason for a new tax - there were four of them in the original energy bill - Congress finds it inadvisable to act quickly.

Mr. Carter's loss of initiative is not, in this case, Congress's gain. The long war of attrition through the Senate and now through the House-Senate conference has not visibly helped any of the reputations at the Capitol. Viewed from a distance, the picture is dominated by lobbyists, ideological zealots and every kind of parochial interest. That gives Congress its own interest in getting a bill passed, but not necessarily a bill that looks much like Mr. Carter's.

Next week Mr. Carter will begin his second year in office. The record so far is a respectable one, notable for good intentions and a steady spirit. But the year is not ending with the kind of achievement for which he had hoped. The reasons for that shortfall do not seem to us to lie beyond comprehension - or beyond remedy.