THE ADMINISTRATION is pursuing a broad

theory of the budget that sometimes gets obscured in the scuffling over numbers. The idea is to push Congress toward something very much like a parliamentary budget that's passed in one piece. It isn't Mr. Reagan's invention. The principle was established by Congress itself in the 1974 Budget Act. But in practice there's been a good deal of congressional backsliding.

The reason for the perennial deficits, in the administration's view, is the fragmentation of political responsibility. As the system has been working, every subcommittee struggles to strengthen its own programs with little concern for the final totals. You do not have to approve of Mr. Reagan's budget priorities or his plans for further spending cuts to agree that this diagnosis is essentially correct. For a current example, you have only to look at the farm bill as it emerged from Sen. Jesse Helms' Agriculture Committee. Sen. Helms is a great believer in balancing the budget, but not at the expense of the agricultural subsidies--which, among other things, will once again provide the country with vastly more milk and cheese than it needs or wants.

The White House has now told all federal agencies to reduce their spending by a flat percentage without waiting for further congressional action. Legally, the administration is asking Congress to defer this spending--and is thinking of burying the committees in a blizzard of formal deferral requests. Many valuable programs are likely to be damaged by this kind of indiscriminate reduction. But the budget deficit is now rising again. In the year just ended it was about $60 billion. Without further action, in the year now beginning it will be $80 billion.

To refine your own sense of these choices, it's helpful to think ahead six months. Where, in your view, ought the budget to stand by April?

One possibility--the least likely, but the one to which the administration is committed--is a series of substantial spending cuts immediately, and another round, even deeper, next spring.

Another possibility--the most sensible, but one that the administration opposes--is to go easy on further spending cuts for the present, give the country time to adjust to those already made, and bring down the deficit with tax increases. Wouldn't it really be better to raise the gasoline tax than to cut Medicare and Medicaid?

The third possibility--the least satisfactory and, unfortunately, the most likely--is a return to stalemate with the administration denouncing Congress, Congress responding in kind, a rising rate of federal borrowing pressing on the credit markets and, consequently, interest rates rising again--unless the country is in a prolonged recession. That's a deeply troubling prospect. If Congress doesn't like the administration's present tactics to restrain spending, Congress has an opportunity now to produce something better. It also has an obligation not merely to protect favored lobbies, but to deal with the budget --outlays and revenues together--as a whole.