The rising rate of inflation is the biggest - perhaps the only - failure of the Carter adminstration to date, and it looms as the primary threat to the president's second term.

For it is a cruel fact politics that unemployment doesn't matter much as long as it is confined, as it usually is, to those who don't vote: namely the minorites and the young.

On the other hand, those who are most hurt by inflation - the aging, the retired and the middle class - make up a bloc of probable to certain voters. If they were to vote their savings accounts right now, they would not vote for Jimmy Carter.

So the question is: What can Carter do about that? A set of answers is being offered by a group of young Washington ecomomists headed by Gar Alperovitz who call themselves the National Center for Economic Alternatives.

They believe Carter's first job is to recognize that the current inflation has little to do with textbook causes of inflation. That is, it has little to do with an effort at full employment; little to do with balancing the budget, and therefore with government spending; little to do with excessive wage demands, and little to do with the money supply.

It results instead, so their argument goes, from two major jolts: the increase in the cost of energy imposed by OPEC and the increase in the cost of food imposed by the world shortage from 1972 through 1974.

As a result of those jolts, most Americans have had little or no real gain in their incomes. Wage pressure is not the cause of our present inflation. Wage earners are still trying to catch up.

So Carter's second job would be to insulate the economy from further jolts, such as another OPEC price increase, another food shortage, an increase in the Social Security tax and so forth.

To install that insulation, it would be necessary to impose export controls on food in times of world shortage, to break the link between world and domestic energy crisis by allotment or allocations and to persuade Congress to shift a part of the Social Security burden to the incomt tax.

None of those steps are radical. We already have a price system for energy, though Carter would have to make a complete turnabout in his present energy plan and try to hold down the price of necessity usage rather than permit it to soar. A shift to the income tax as a means of saving Social Security is already being talked about in Congress.

So the installation of shock absorbers is within Carter's ability, even though he would have to admit that his stalled energy program was at least a partial mistake.

The shock absorbers would take care of the price for two of the big four items in American consumption. Food, energy, housing and health costs take 70 percent of expendable income from 80 percent of the American people.

The next step would be to encourage HEW Secretary Joseph Califano in his present effort to reduce medical costs and to allocate more money to the housing market, thus reducing interest costs.

To repeat, none of those steps are radical. They would be opposed by the special interests concerned: the oil companies, the big grain exporters and the medical profession. But if they were taken as steps in an overall effort to halt inflation, Carter would be striking at the one issue that concerns the majority of the American people.