President-elect Reagan won by a bar majority of the popular vote. But President Carter, with only 41 percent, lost big. So disappointment with his poor record and tapioca style had to count a lot in the outcome.

A week foreign policy also mattered. Pat Caddell, Carter's pollster, told the Cabinet on Election Day that the last-minute flurry about the hostages in Iran, and the impasse that then developed, cost the president five points. That could be merely the alibi of the losing pollster. But Americans did resent the holding of the hostages and did find in that drama a sign of waning influence around the world.

Still, there was at work a deeper spirit of resentment, a sense of having had it, of being fed up. That spirit worled in the North and in the South, and in the East and in the West. It worked on men and on women, and on blue collars and on white collars. It worked against Carter, but also against candidates unconnected with him or his foreign policy. It worked against Gov. Bill Clinton of Arkansas and Sen Bob Morgan of North Carolina and Rep. Al Ullman of Oregon. It worked, in other words, across the board.

Inflation produced the pervasive negative spirit, that will to have done at any cost. It has been Public Enemy No. 1 for years, and it was the big issue in the campaign. If the election afforded any single mandate, the message said: "Stop inflation."

Certainly the message comes in season. The core rate of inflation -- that is, the rate by which prices rise independent of outside shocks from such variables as food and energy shortages -- is now over 9 percent annually. With the country emerging from recession, moreover, inflation is rising again.

Ronald Reagan and his associates, however, are poorly positioned to apply the brakes. The president-elect ran on a prosperity theme, promising "jobs, jobs, jobs." He also pledged higher defense spending. He will have to eat a lot of rhetoric if he is to avoid a big tax cut next year and a hike in the military outlays. So it will be hard for him to achieve the balanced budget that is a condition of a tight fiscal policy.

A tight monetary policy will come much more easily. Reagan and all his economic advisers believe in squeezing credit as a check on inflation. Their theory is that a tough stance on the money supply communicates to business and labor the need for restraint in raising prices and wages.

But experience shows that business and labor get that message very slowly. Long before they do, the present recovery will self-destruct. Business activity will slump, and unemplyment will hold high. With capacity idle, companies will be loath to invest. Productivity -- or output per man hour -- will stay flat.

In those conditions, the economy becomes a sitting duck for outside inflationary forces. Two are already in the wings again. The conflict in the Persian Gulf foreshadows an oil shortage and a new rise in energy costs. Bad harvests prefigure increasing food prices.

Those shocks could be cushioned by government actions to limit price and wage increases. But Reagan and his advisers regard such intentions as heresy. So the prospect ahead is for a long period of slow growth and high inflation. Maybe Reagan can govern effectively in that atmosphere. The Democratic opposition has been picked to pieces. Liberalism, the quintessential party faith, is a passion torn to tatters. Practically every constituent group strayed from the famous coalition this year and ended up for grabs.

Some see in those developments a "realigning election," like that of 1932, in which a new governing majority is formed. There is even talk of a "new era" in American politics.

What I see is a "de-aligning election." Large chunks of the old Democratic coalition have indeed broken off and are now adrift. Reagan can take them in hand -- but only on condition he masters inflation.

The odds, however, are against it. Reagan comes on the presidential stage having, like most of his recent predecessors, promised more than he can deliver. If he flounders, he will be vulnerable to the next political gunslinger able to capture a public that is fickle in heart and superficial in mind. His situation, in other words, is not so different from that which brought grief to the last four presidents. So, far from marking a decisive break with the past, the election of 1980 looks to me like more of the same old era.