Rep. John B. Anderson (R-Ill.), one of the hordes of Republicans seeking his party's presidential nomination, did something the other day that makes him stand out in this crowd. He suggested a 50-cent-a-gallon tax on gasoline. If there were a handbook for candidates, one chapter surely would begin, "Don't propose a gasoline tax." But Anderson's very obscurity and the lengthy odds against his success give him some extra liberty to violate the rules, even perhaps to the point of saying something he believes.

There is, of course, virtually no chance that a gasoline tax will be passed anytime soon, which is unfortunate. By now, we ought to have realized that many of the arguments used against such a tax are a sham. The poor (in whose name a tax always is protested) don't drive much simply because many of them can't afford to own cars. As for regions that depend most heavily on automobiles -- and therefore might feel the tax most -- they actually have the greatest interest in reducing overall gasoline demand because, in the event of scarcity, they will be hurt the most;

No matter. We choose to leave ourselves at the mercy of an unstable world oil market -- which ultimately enacts the tax for us -- rather than to acknowledge that the essence of our oil problem (as opposed to the "energy problem") is largely the autombile, and that coping with it involves pushing people towards more efficient vehicles and traveling habits. The best government can do is create a climate in which individuals acting in their own self-interest also act in the national interest.

This is a polticial failure. The most worn cliche about politics is that it is the art of the possible, but that isn't an explanation so much as an excuse. The artistry of politics -- aside from winning elections -- is packaging and promotion: matching problems with remedies that seem both practial and palatable.

As its worst, this is a demeaning, deceptive process, but at its best it draws together different strands of national experience and combines them in a way that makes contemporary problems seen understandable and manageable. The current generation of politicans may wonder why it is held in such low public esteem; one reason is its inability to perform this vital function.

As Anderson's proposal suggests, the job ought not always be as difficult as it is portrayed. No one, of course, likes to pay higher prices, and politicians are loathe to raise the price of anything, especially something as conspicuous as gasoline.

But the untold part of this story is that a gasoline tax is a stupendous money raiser; and -- other things being equal -- a higher gasoline tax allows you to lower something else. Even if a 50-cent-a-gallon tax reduced consumption by 6 percent or 7 percent (which is about 500,000 barrels a day, or 10 percent of Japan's total oil consumption), it still would raise about $50 billion annually. That is about 10 percent of the total federal receipts projected for next year.

The government needs that money. One of the nasty little facts that no one in Washington is mentioning very loudly -- to the public, at any rate -- is that it will be very difficult, maybe impossible, for the federal government to cut overall levels of taxes in the 1980s.

The reasons for this squeeze are plain enough and probably won't be altered much by the 1980 election, no matter who wins. A large part of the federal budget (nearly 55 percent) goes for two purposes: defense and the elderly. And spending for both of these probably will be increasing strongly in the 1980s.

On the one hand, the over-65 population will be rising significantly faster than the overall population: it will be up 25 percent between 1979 and 1990 against a projected 10 percent overall increase. Unless benefits are reduced -- which is unlikely -- this means higher Social Security and health spending.

At the same time, there is little or no prospect of substantial defense cutbacks. Between 1955 and 1978, defense spending declined from about 10 percent of national output to 5 percent. There now seems to be a consensus that it shouldn't drop any further and, indeed, the argument is between those who think it ought to rise 3 percent annually in "real" terms (after inflation) and those who argue for 5 percent.

Based on such considerations, Rudolph G. Penner, former chief economist for the Office of Management and Budget, has estimated that to achieve a balanced budget by 1990 would require that spending for all other (nondefense, non-elderly) programs would have to decline 0.5 percent a year in "real" terms. Even so, taxes would equal 20 percent of gross national product, which would be slightly higher than in all years but two (1969 and 1970) since 1958. And Penner's analysis deliberately includes a number of optimistic assumptions: a growing economy, revived productivity and only a 3 percent increase in real defense spending.

Against this background, the question for the 1980s is simple: How do we tax ourselves?

Do we tax labor via higher Social Security taxes (already scheduled to rise sharply) and higher marginal income tax rates? Do we tax capital and investment by keeping those rates high? Do we tax ourselves via inflation by running large deficits, which tend to spur higher money growth and more inflation?

Or do we ease these tax burdens by imposing a tax on a critical commodity whose supply is scarce and far more important, uncertain?

The answer seems obvious enough. We need to create a margin of safety between domestic oil demand (two-fifth of which is gasoline) and worldwide oil availability so that we will be less vulnerable to interruptions. President Carter's solution of creating a synthetic fuel industry -- even if it worked, which is questionable -- wouldn't yield results until the mid-1980s. His "windfall profits" tax wouldn't affect the basic revenue balance because the annual sums are small and much of the money would be funneled into synthetics.

Perhaps there are better ways of doing it than a gasoline tax: a heavy tax on imported oil, for example. But the main point is that the political system isn't posing the choices. For six years, a Democratic Congress has created a hopeless confusion and paralysis on the energy issues. Republicans talk of lower taxes and higher defense spending in one breath as if there were no conflict. Theirs is a collective poverty if imagination.