THE BUDGET continues to disintegrate. Last week a House committee blew a multibillion-dollar hole in the document on behalf of veterans. This week the Senate seems about to stage a similar breakout on behalf of farmers. The agriculture appropriations bill is on the Senate floor. Farm-state Democrats want to add about $10 billion in "emergency" payments that wouldn't count against the spending limits to which both parties continue to pretend to subscribe. Republicans, fearful of being outbid, are likely to have their own proposal. A similar bidding war helped drive the budget last year.

Agriculture joins a distinguished list. The budget rules already have been bent this year for defense. The House has voted to bend them for aviation as well. Even the census has been declared an emergency. The House Republican leadership, in order to pay for other appropriations bills, has taken billions from what is likely to be the final bill of the year for the departments of labor, health and human services and education -- the theory being that Democrats ultimately will join in salvaging the measure to protect their favored programs. The Republicans need to go through the exercise -- pretend they're holding spending down -- or else they won't have enough money to pay for their tax cut, the ultimate budget buster. The president meanwhile dangles a major Medicare benefit increase -- for prescription drugs -- when not enough money is in sight to pay for even the current benefit structure.

In the case of agriculture, as in many of these, the problem isn't so much the extra spending, for at least a part of which a good case can be made. The problem is the pretense that somehow the predictable spending won't occur. The pretense is the basis on which they project the "surplus" that then allows them to spend still more. The farmers are hurting, as they were last year, because of a combination of low prices and unfavorable weather -- and the 1995 farm act, which sought to wean farmers away from government price supports, is not as responsive to low prices as was the traditional farm program that it replaced.

Democrats want not just to supplement the 1995 act but to roll it back in part, thereby wringing an admission from Republicans that they made a mistake in passing it. Republicans, if last year is an indication, will support a supplement, but on a one-year basis only, without a rollback and the acknowledgment that it would entail. Our sense, this year as last, is that there ought to be some increased aid but that it ought to be better targeted on needy farmers than it is likely to be in the end. More important is that the payment levels used in estimating likely future spending be realistic. Then the members won't go around, as they are again this year, spending "extra" money that their own behavior makes it unlikely the government will ever have.