When the boulders finally came to rest, amid the remants of the New Deal temple that was swept from the summit with them, it was clear to all the wise men in Washington what historic shift had occurred. A Reagan Revolution, comparable to the Roosevelt Revolution of a half-century before, had altered the American political landscape, with profound implications for the nation and world inthe closing decades of the 20th century. America had swung sharply right. The long-sought mandate for ideological change had been achieved. So, at least, it is being said.

Here in the capital city, in that normally smug -- and now shocked -- enclave of political philosophers, operatives, pollsters, assorted media manipulators and "press wizards," to borrow Hunter thompson's phrase, the tut-tutting, head-nodding and other signs of collective judgment are nearly universal in the aftermath of Tuesday's surprise. But before this latest wisdom becomes chiseled in marble, here's an iconoclastic word of caution about the Great New Trend.

Ronald Reagan received little more than half -- 51 percent to be exact -- of the presidential ballots cast last week. He actually takes control of the nation's destiny with even less of a popular mandate than his percentage of the vote indicates. This election marked the lowest turnout in 32 years, thus continuing the downward slide in recent successive presidential contests. Of the approximately 165 million Americans eligible to vote last Tuesday, Reagan won the support of about only one of every four.

The 1980 returns are also instructive in terms of notable landslides in the modern era of American politics. Franklin D. Roosevelt received 57.4 percent of the popular vote when he was first elected in 1932. Four years later, when he defeated Alf Landon by an Electoral College margin of 523 to 8, he took 60.8 percent of the votes. His popular vote percentages in his last two terms were 54.7 and 53.3. Dwight D. Eisenhower was supported by 55.1 an 57.4 percent of the voters in his two terms. The greatest of all the popular margins was achieved by Lyndon B. Johnson in 1964. LBJ exceeded Fdr's 1936 figure by winning 61.1 percent of the vote. In 1972, in the last comparable presidental tidal wave, Richard Nixon virtually matched those tabulations by carrying 60.7 percent.

The point is not churlishly to deprecate Reagan's great victory, nor to minimize its true sugnificance by the almost always dubious citing of old statistics. But it's premature to read Reagan's triumph as some sort of ideological mandate. If that's the conclusion the Republicans draw, it's quite likely they will have missed their greatest opportunity to rebuild their party and reshape the country.

George Wallace had it right long ago when he urged voters "to send them a message." the "them," of course, meant all those in charge in Washington. Wallace was not the first to run against Washington; Jimmy Carter exploited the common frustrations skillfully enough to win last time, and on much the same themes as Reagan. He, too, wanted to cut back the bureaucracy, slice through the red tape, eliminate the stifling -- and stupid -- regulations and get government off the backs of its citizens. His failures gave Reagan's similar campaign assertions all the more force in 1980. But Reagan was able to capitalize on much deeper discontent.

Voters this fall, to a degree unmatched in the last generation, were saying they were troubled by an America in decline at home and abroad.They blamed, first of all, Carter for seeming incapable of offering any believable solutions to the problems of inflation and unemployment and for failing to reverse the impression that the United States had become impotent in world affairs -- a modern Gulliver unable to protect its own people when seized by a band of terrorists. Not since Herbert Hoover, another politician with an engineering approach to problems and a strong humanitarian bent, has an American president been so personally rejected by the American people.

The continuing crisis in Iran further intensified these already powerful emotions. Americans awoke on election morning to see the frustrating series of events concerning the hostages played out before their eyes on television. One particularly memorable sequence, over CBS, ended a year-long reprise of the hostage ordeal by showing a tattered American flag stirring limply in the breeze. It was, in its way, a symbol of all the anguish over the nation's unhappy sense of its present position.

Voters obviously were rendering an equally harsh judgment on the inability of the Democrats to offer solutions. They, after all, controlled the Congress, and they singularly had failed to arrest the nation's decline. What people wanted was something that held promise of working -- and they certainly weren't getting it from Democratic rule at both ends of Pennsylvania Avenue. But that doesn't mean their disgust sent them searching for some ideological banner to follow.

What Reagan and the Republicans now have is a chance to start fresh, to show the country they can offer programs and policies that have a prospect of working. If so, they finally can fashion their new majority, and they will deserve it. Their problem lies not just in the inherenet difficulities of governing today, it stems from the attitudes they strike. Too often in the years of their minority status, they have been crippled by their negative approach. They were more often against thean they were for. More than anything at this point, the country wants to feel positive about itself, to believe the system can function, that problems can be solved, that the future can be better than the dismal present.

In his news conference Thursday, Reagan struck that positive note. As president, he said, he represents all Americans. He didn't say so, and didn't have to, but that implies a recognition that he must reach beyond the narrow ideological fringes to govern effectively. What America needs today, after so long a period of failures, is not a celebration of another political victory and talk of another political wave lifting us to greater heights -- another Great Society of the left followed by another New Majority of the right -- only to be dashed again by heightened expectations that produce further disillusionment. What America needs is simply to have a success.