As the season devoted to wretched excess begins, how fitting that Congress and the White House are giving the nation a federal budget that is not separate servings of reasoned legislation but a revolting omnibus hash. Take one Halloween grab bag, an overstuffed Thanksgiving turkey and a mystery-filled Christmas fruit cake, shove it in the blender, set on frappe.

After neglecting it responsibilities for months to pass eight separate appropriations bills, and now in a burning hurry to hit the campaign trail, the House and Senate are about to pass an omnibus spending bill. It costs $500 billion, it’s bigger than an unabridged dictionary, it’s content is largely unknown. Except, of course, to the lobbyists who compiled it.

This is such an awful way to legislate that it’s hardly right to call it legislating. At times such as this it is tempting to revive that the old gag about the similarity between making laws and and making sausage, except to do so would be an affront to good sausage makers everywhere.

This inexcusable situation is, of course, all Monica Lewinsky’s fault. Democrats, hoping to divert attention from President Clinton’s little problem, were as stubborn as a minority bloc can be on those social issues — education and farm aid, in particular — that are quaintly referred to as party values. Republicans, almost forgetting that they were cast as the villians in the 1995 government shutdown, were in no hurry pass anything, hoping to demonstrate that the damaged president is unfit to lead. That both sides caved and had to engage in a furious last-minute swap meet proves that when amateurs play a game of brinkmanship, everybody loses.

Everybody except, of course, President Clinton. Even Republicans grudgingly admit that by pushing the nation’s business to the edge of banmkruptcy, they gave Mr. Clinton a full week of nightly news sound bites on such non–Lewinskian topics as Social Security, education and HMOs. As Congress adjourns to campaign, the last image voters have is not of the vote to begin impeachment proceedings, but of the president looking presidential again. He may not be good, but, by golly, he sure is lucky.

True, the normal process of passing appropriations bills is hardly savory. But at least the bill for, say, the Commerce Department contains items somewhat related to commerce and the debate leading up to it is somewhat relevant to the issues at hand. This bloated omnibus contains everything but rhyme or reason. Why, for example, did Democrats agree to a few billion more for defense in exchange for a few billion more for farmers? What’s the connection? Why did Republicans, generally loathe to inject the federal hand into local education, approve funds to hire 100,000 new teachers but nothing to repair dilapidated school buildings? Why was a multibillion-dollar hike in military pensions that even the military says needs further examination for cost and fairness rushed through while a modest plan to help disabled people move from welfare to work by letting them buy into Medicaid didn’t make the cut?

But leaving such troubling questions unanswered is a small price to pay for what Congress gained — the ability to return to the home district to crow about the can-do spirit of bipartisanship that prevailed. And not to worry. Before they sign anything into law, both parties promise they’ll take a day or two to dig into the details of this half-trillion dollar casserole. They’ll just have to hold their noses as they do so.