The big policy question for the fiscal year 1984 budget is the same as it was a year ago: should taxes be raised?

Congress recently threw down the gauntlet when the two budget comittees included a tax increase of about $30 billion in their suggested budget resolutions. "A plague on both your houses," says the president, who refuses to accept any tax hike this year.

The president is right on this one. With the economy barely past the bottom of its worst slump in decades, this is an inauspicious time to raise taxes--unless the Federal Reserve is about to deliver a much easier monetary policy than anyone anticipates.

The youthful recovery looks extremely fragile. While much was made of the announcement that real GNP grew in the first quarter of 1983, closer examination reveals that the GNP report was a disaster. If the preliminary numbers are correct, more than two-thirds of the reported growth came from a slowdown in the rate of inventory liquidation. Growth of real final sales (GNP less inventory change) slackened dramatically from the healthy rate achieved in the previous quarter. The bloom is off the boom, Shakepeare might have said.

So raising taxes this year runs the risk of exposing the economy yet again to the slings and arrows of outrageous recession. But if we don't raise taxes, you ask, how will we ever get the sea of deficits under control? The answer is that taxes must indeed be raised--sometime.

Under current tax laws and spending plans, the administration projects a deficit in fiscal 1988 that is roughly 6 percent of GNP, an alarming figure. If policy is not adjusted between now and then, government borrowing may exceed personal saving. Polonius ("Neither a borrower nor a lender be") would be distressed, and with good reason. If all personal saving is used to finance the government deficit, firms must finance their own investments or turn to foreign lenders. Investment is sure to suffer.

Though the crowding-out problem is not upon us yet, it is not too early to start whittling away at those mountainous out-year deficits. But measures designed to close the out- year deficits need not--indeed, should not--have much revenue impact in fiscal 1984. We need, instead, to mount an attack now on future deficits.

The president's proposed "contingency tax" does exactly this. The contingency tax consists of a surtax on personal and corporate incomes, and an excise tax on petroleum, to be imposed in fiscal 1986 if the economy is growing and the deficit is not yet below 2.5 percent of GNP. The contingencies seem very likely to come true. So the economics of the proposal seem right.

Now for the bad news. The politics of the proposal are so ludicrous that it is widely regarded as a gimmick designed to postpone the day of reckoning. The contingency tax is embodied in no legislation. It is no more than a promise that some future Congress will do what the present Congress finds unpalatable. Such temporizing can hardly be expected to calm the jittery credit markets.

If Congress is correct to spurn the contingency tax, and the president is correct to reject a tax hike this year, where does this leave us? That, as the man said, is the question. Here is part of the answer. (The rest must come on the spending side.)

Congress should enact legislation now that produces revenue for future budgets, starting perhaps with fiscal year 1986. The additional revenue should amount to at least 2 percent of GNP. And there should be no contingencies except the obvious (and unstated) possibility that subsequent congresses will repeal the law.

From where will the revenue come? In a way, this is less important than that it come from somewhere. Congress will no doubt think of other ideas, but here are two relatively benign ways to bite the bullet.

The most inviting way to raise revenue is to mount a full-scale assault on the hundreds of loopholes that now deface the tax code like so much bad grafitti. Tax reform badly needs support from the citizenry, because it certainly won't get any from Washington's legions of lobbyists.

And while I am daydreaming, here is another possibility. Let Congress enact three consecutive 5 percent increases in personal income tax rates, to take effect at the beginning of 1986, 1987, and 1988. At the end of the three-year period, tax brackets should be indexed. But we shouldn't stop there. We should also index the definition of income from capital, so that only real interest and real capital gains would be taxed, and limit the tax deductibility of interest to real interest payments.

On the corporate side, depreciation lives should be lengthened to correspond to economic realities, and then depreciation allowances should be indexed to end inflationary distortions for good.

Lest anybody miss the message, the bill might be named the "Recovery from the 'Economic Recovery Tax of 1981' Act.'