IT'S GOING TO BE an uncomfortable year for the politicians in charge of economic policy. For three decades they have been telling the voters that skillful management can consistently produce high employment and steady growth. They no longer believe it.

Fortunately for the Carter administration, most of the voters have also ceased to believe it. Voters perceive that the people in power -- and their opponents as well -- are now immobilized between the fear of higher inflation and the fear of recession. The remedies to each can only make the other worse.

The hard truths of 1979 were not welcome, but at least they make the job for 1980 clearer. The first of those truths is that, contrary to a great deal of official reassurance over the past three administrations, inflation will not wind down by itself. It has become self-perpetuating and will continue until spending, both public and private, comes down a bit.

The second truth of 1979 is, similarly, that oil prices are not self-stabilizing. The oil exporting countries are going to keep piling one increase on top of another until the industrial countries cut back substantially. That won't happen as long as governments keep trying to shield consumers from the full impact of those prices increases.

There was also the lesson that the foreign exchange rate of the dollar has now become a constant and dramatic check on American domestic economic choices. The sudden dive by the dollar last fall, and the sharp increases in interest rates required to rescue it, demonstrated the sensitivity of foreign markets to American intentions, real or imagined.

That's a gloomy little list. But at the bginning of a new year it's also necessary to touch on a few other truths. In the past several years most Americans have been living better, and longer, than ever before. This country does not protect as well as it might those citizens who are sick or poor. But it gives them better protection than at any time in the past. As for the coming recession, maybe only luck has postponed it. But maybe unemployment stayed down in 1979 at least partly because a lot of Americans with jobs accepted, through inflation, modest reductions in their real incomes.

The administration's policy has been frozen by uncertainty and conflicting values. Perhaps that freeze will continue well into the new year. But a good many individual Americans understood that the economy is moving through a difficult time, and they have begun to react, carefully and sensibly, in ways that are helpful to the country as well as to themselves. Not many people will catch up with inflation in 1980, and trying to do so is damaging. There won't be as much gasoline for most people, and trying to get more will hurt everybody. The coming year looks like a time for retrenchment, to prepare for renewed growth beyond it.