TAX-CUT FEVER is sweeping through the Senate like chickenpox through a kindergarten. THe final votes on the tax bill have turned into a panic-stricken rush by a large majority of the senators to get on record in favor of cuts - cuts for the rich, cuts for the poor, cuts of years far into the future. The House version of the bill would cut taxes $16.3 billion next year. President Carter thinks a $20-billion cut would be about right. The Senate's cuts amount to something over $30 billion for the coming year alone, and much more later.

That kind of bill "would not be satisfactory," President Carter dryly observed in his press conference yesterday. As he said two or three times, he will veto the bill if it looks anything like the current Senate version. He went a step further, adding the thought that he does not favor a lame-duck session after the elections. He deliberately raised the dreadful prospect of no tax cut at all this year if Congress doesn't give hime responsible legislation the first time. He was addressing the buzz of speculation that of course the Senate would misbehave, and of course the president would veto the result - and of course Congress could quickly rewrite the bill after the election returns are in. Mr. Carter is telling Congress not to count on his cooperation.

Mr. Carter's admonitions strengthen the probability that the House-Senate conference will drop most of the Senate's more bizarre and adventurous amendments - the most notable of which is the Nunn proposal. Sen. Sam Nunn (D-Ga.), has induced the Senate to go along with his plan for a semi-automatic repeating tax cut, a piece of machinery that brilliantly illustrates the intellectual confusions into which the Senate has fallen.

A lot of senators have evidently concluded that it is dangerous simply to cut taxes. Lower taxes suggest larger budget deficits, and a lot of people blame the deficits for the inflation. That's why senators are now devoting the same single-minded concentration and mechanical ingenuity to the invention of a non-inflationary tax cut that Cyrus McCormack brought to the first reaper. The Nunn plan calls for large tax cuts staged over the next five years - but all of them contingent on a greatly reduced rate of growth in federal spending. It would also require the federal budget to shrink in relation to the national economy.

It will be recalled that these ideals - lower taxes, limits on spending, diminishing deficits - were a prominent part of the platform on which Mr. Carter ran for the presidency. The Democrats in the Senate have now decided that he is right, but, characteristically, they are overdoing it. There is a vast difference between campaign utterance and actual legislation. Mr. Carter has decided, wisely, to back off some of his original deadlines, like the balanced budget in 1980, because they threaten economic stability. The Nunn amendment carries the same danger.

If there should be a recession next year, federal spending would rise rapidly because of the increase in unemployment benefits, welfare and Social Security payments. Under the Nunn amendment, the scheduled tax cuts would not go into effect. But it is precisely in a recession that the case for cutting taxes is strongest.

There's a certain superficial appeal to the idea of an automatic pilot to govern federal tax and spending policies. To Sen. Nunn and his supporters, no doubt it seems a good and useful disciplinary device: If you don't behave and keep spending down, you don't get your tax cut. But it's the kind of mechanical discipline that can turn mild recessions into deep and prolonged ones. Steering the federal system is work that has to be done by hand. The need for adjustment is constant, and the unpredicted continually happens. The automatic formula for fiscal discipline is a thing for sensible people to approach with grave doubt and deep suspicion.