THE IDEA of a freeze on federal spending seems to be drawing more support in Congress. It is the product of rising anxiety over the budget deficit, and exasperation with the laborious process of cutting it by any more conventional method.

A spending freeze in the broad and simple form is, of course, impossible. How can the federal government freeze unemployment compensation, for example, when it cannot freeze the number of people unemployed? How can it freeze Medicare when it cannot control the hospital bills that Medicare pays? But, on the opposite page, Sen. Ernest F. Hollings proposes a more sophisticated and careful variation on the theme.

He makes the right exceptions, among the major categories of the budget. If the forecasts turn out to be right, a freeze on any outlay will mean a real cut of about 5 percent a year. A cut of 5 percent should not be treated as the end of the world, even in categories as sensitive as the pensions. Since Social Security benefits were overcompensated for inflation in the 1970s, it is not entirely unjust to undercompensate them for a limited period in the 1980s--as long as the savings are part of a broad national effort to slow down the automatic growth of the budget.

The other half of that broad national effort, in Mr. Hollings' view, is to cancel the income tax cut due next July and repeal the law that would index the tax brackets to the inflation rate beginning in 1985. Our own preference would be to leave the July tax cut in place while the economy struggles toward a recovery--although we would have to concede that, the response to the last tax cut having been invisible to the naked eye, the case for preserving the next one is not compelling. As for indexing the tax brackets, the senator is plainly right.

President Reagan argues that the country ought not to raise taxes in a recession. It's not a question of raising taxes. It's an attempt to offset some of the progressively larger tax cuts that were contained in that gigantic 1981 tax law, various provisions of which will continue to take effect for several years to come. Mr. Hollings would not leave the country with a higher tax burden than at present, but he would have taxes decline less rapidly than the present law mandates.

The economy won't grow adequately until interest rates come down, and the rates won't come down until the deficit does. Sen. Hollings' proposal is not perfect in every aspect. But he offers a consistent and intelligible response to that huge and growing deficit. That is more than Mr. Reagan, at his press conference this week, could do.