Sen. Paul Laxalt of Nevada, the general chairman of the Republican Party and an authentic presidential intimate, recently told Lou Cannon of The Post: "I think there's a growing recognition that Ronald Reagan inherited his problems, that he's doing his best and the economic problems were more severe than anyone thought, including him." With this sympathetically straightforward statement, Paul Laxalt has pronounced optimism--his friend, the president's most distinguishing public characteristic--officially dead.

Now we are told by the GOP chairman that the president should be judged not on his performance but on his effort, for which Paul Laxalt gives Ronald Reagan an "A." When Jimmy Carter was president, his loyalists explained that our nation's problems, in addition to being mostly beyond our control and comprehension, were also "intractable." In 1980, Reagan, the can-do candidate, would have none of that, thank you, and "Hold the malaise, too." In 1983, the nation's unsolved problems, according to Reagan loyalists, turn out to be "structural." From intractable to structural in just 36 months.

In the case of Reagan, optimism was never a simple campaign device; it was the very core of the man. And for good reason. Here was a poor boy whose economically uncertain youth was made even more so by the Depression and his father's alcoholism, who became a sports announcer and a movie star, governor and president. In 1980, Reagan touched the native optimism of America on the way to his landslide victory that November. It could be done, he proclaimed, and he had the plan to do it.

Just as he had won in the country, he won in Congress, spectacularly. Perhaps he would have been better off then, for his present political good, to have been less successful in passing his program. In 1981, Reagan got everything he asked for from the legislature, which for any elected executive is a problem: the promised results were expectantly awaited.

When the painless and ouchless prosperity did not arrive on schedule, we were told to be patient. Now it turns out that time would not be enough, because the problems were "structural." Paul Laxalt says that his friend, the president, is doing his best, and that should be good enough. But by so doing, the senator declares optimism in this administration to be null and void. That is announcing nothing less than the end of the first Reagan administration. Reagan without optimism is nothing less than Harry Truman without feistiness, FDR without confidence and eloquence, Jack Kennedy without vitality and youth.

Ronald Reagan may recover from his present political difficulties. He may run again and he may win. But the message of his presidency is now changed. The presidency itself is changed. No longer, according to his First Friend, is there so much a mission to be accomplished as there is a continuing crisis to be managed. Of course, that was not what Laxalt and Reagan were selling in 1980. Then, the problems were manageable and the optimism was on full. Now, the optimism is depleted and the president should get "A" for effort.