THE LONGER I watch politics and politicians, the more I am willing to settle for a few modest virtues in the people who offer themselves to lead the rest of us. What I want to know, first of all, is whether the politician does his own thinking or hires experts to do it for him.

This is the hardest question to answer with certainty, but in an age dominated by specialized experts, I find it much more compelling than whether a candidate is "liberal" on this, "conservative" on that, "radical" on something else. Give me a president who listens to his own curbstone commonsense, who has the nerve to shoo the experts out of the room when their advice smells of disaster. If you want to talk about "leadership," the new buzzword of national politics, I think the great leaders, from Jefferson to FDR, all shared that quality -- the courage to do their own thinking.

If Jimmy Carter loses in 1980 and replaces Herbert Hoover as the great goat of political legend, I think the post-mortems will identify this as his fatal weakness: that he listened too well, too respectfully, to his experts, especially his economists, that it did not dawn on his politician's soul until much too late that they did not know what they were talking about. I hardly need to point out that this weakness before "experts" is shared by too many of our 1980 candidates.

The Carter administration's economic policy now resembes a scared rabbit frozen in the middle of the highway, not sure which way to jump to avoid disaster. If the economists are correct, Carter the candidate is soon to be hit by a truckload of bad news -- a recession plus immoderate inflation. Only the economists have been wrong. Not just wrong now and then, but wrong consistently throughout Carter's term in the White House. One of the president's premier political advisers claims contemptuously that economic advisers inside and outside the government have a no-hitter going. "Their forecasts have been wrong for the last 12 quarters, starting in the fourth quarter of 1976," he asserts.

Might they be wrong again? The anonymous political adviser sincerely hopes so. Otherwise, his candidate faces the most devastating combination of economic ailments in the election season ahead. The political history of the last 30 years indicates a fairly constant rhythm -- economic upsurges in biennial election years produced by politicans who manipulate the economy. When there is a downturn, the incumbent party loses -- loses seats in Congress or even loses the White House.

Although everyone's attention has been riveted on Iran of late, we will rediscover before too long, I suspect, that this persistent rhythm still dominates national politics. The pattern was brillantly documented by political scientist Edward R. Tufte in his book, "Political Control of the Economy" (Princeton University Press, 1978), but the author acknowledged that his research only confirmed a basic truth already known to smart politicians. What Richard Nixon knew when he pumped up the economy in 1972 was that a rather mild recession had defeated him in 1960.He wasn't going through that again. His manipulation of the economy -- assisted by such free-market stalwarts as George Schultze and Arthur Burns -- contributed greatly to the economic gyrations of the decade ending.

By contrast, after listening to his experts for several years, Carter has managed to arrange the political-economic calendar in the worst possible way. Instead of having a recession in 1979 so that 1980 could be a bountiful year of recovery, Carter is now told by those experts that he faces a recession this spring when he is contending for his own party's nomination. Even if Carter gets past the Democratic challengers this spring, the ill will of recession lingers on politics after the event. In, 1960 the recession was overover long before the November election, but people still felt badly toward Republicans.

Well, you could argue, as Carter's advisers do, that a mild recession wouldn't hurt that many folks directly and, more important, it could break the back of our 13 percent inflation rate. While some people would be thrown out of work temporarily, most would be grateful for the moderating price of hamburger at their grocery stores.

The trouble with that wishful thinking is that the president, listening this time to the expert advice of his energy counselors, has also taken government controls off domestic oil prices. Gasoline at the pump will cost more and more, thanks to decontrol. The economists insist that $1.50 or $2 gasoline will be good for us, but somehow I do not expect most voters to react with gratitude.

Our president may rail at the oil moguls and the OPEC sheiks but, indeed, he has turned over the setting of energy prices to both groups. As the reality of decontrol begins to sink in, I expect the other candidates will point out this connection between Jimmy Carter and the gas pump. Carter may reply that his new "windfall" oil tax takes billions away from the oil companies and gives it to the government, but this money still comes out of the same pockets -- ours.

Thus and therefore, the political-economic history of the last generation would mark Jimmy Carter as a sure loser in 1980, notwithstanding his recent surge in the polls. But Jimmy Carter has this thought to encourage him: History hasn't been working in the last few years.

The president probably knows this better than anyone. The economists keep telling him what their computer models predict for the coming season -- and the coming season keeps proving them wrong. The great surge of inflation in early 1978 shocked the computers. In late 1978, they began predicting a recession soon. The nation is still waiting, a year later, and the computers are still predicting.

If we ask why the computer models were wrong, one important answer is that, after a decade of living with inflation, Americans feel differently about saving money. The psychology of saving and spending has changed, especially among younger consumers, and people have kept on buying things long after the traditional point where they were supposed to get scared and retreat from the marketplace.

Jay Schmiedeskamp of the Gallup polling organization, an expert on consumer attitudes and of the first to recognize this fundamental change, thinks now that the postponed recession will come at last in 1980 -- not because consumers have changed their spending attitudes, but because they are at last running out of money. Per-capita disposable income, one of the key indicators of Tufte's political-economic equations, has been declining for the past year, not growing as Americans have come to assume. So consumers are using their savings and credit to fill the gap. When those resources run out, Schmiedeskamp expects a dismal season -- a recession more severe than the one the Carter administration is forecasting. The experts, by accident, finally may turn out to be right.

Among Carter's political counselors, there is some fragile hope that the public will not hold him responsible for economic conditions this time -- the mature voters now are beginning to appreciate that a mere president can't control these complicated things. Maybe so, but I remain skeptical. What are presidents for if you can't blame them for bad times? Nobody elected an econometric model to run things; we vote for live politicians with eyes and ears, not for unaccountable academic wizards.

This reality -- the notion that we cannot rely on the experts -- separates the sheep from the goats. Some people, especially in Washington, find it terrifying, anarchical, a threat to stable government. Some of us, however, find it exhilarating. We are discovering, in a sense, the limits of the enlightenment, economic and otherwise. If we add up the great policy disasters of our times -- and there are plenty of them -- I think an abundance could be pinned on the narrow experts, expertly advising on issues ranging from fiscal policy to foreign policy, not on the scheming and self-interested politicians who merely wanted to please voters.

The experts who populate this city of public policy tend to frame the arguments self-righteously as a choice between doing the "right thing" or doing the "political" thing in order to get re-elected. Crass politicians tend to see the two as synonymous -- doing the "right thing" means getting re-elected. Obviously, we want a little of both in our political leaders -- a sense of self-interested responsiveness and a sense of higher values. If the people feel pain, throw the rascals out. If times are good, reward the rescals with another term. That sounds crude, but it's not a bad working premise for a democracy.

Maybe Jimmy Carter will repeal it in 1980. Perhaps he will win despite bad times. I wouldn't bet my WIN button on it.