A crucial vote is expected in Congress this week on the fate of the horrendously expensive B-2 Stealth bomber. A major campaign is being waged by the administration, the Air Force, the Northrup Corp., and a grassroots public relations effort in 100 congressional districts. Despite that mammoth push, the B-2 deserves to be grounded.

The B-2 can be justified in a certain military sense, especially since the existing B-52 fleet is very old, though the elderly bombers performed reasonably well in the Persian Gulf war.But the staggering cost - $850 million for each plane - cancels out most of the supposed military benefits. Although the B-2 accounts for half of Northrup Corp. business, the bomber is not some sort of expensive jobs program. If it is not really needed, it should be dropped.

There are at least two reasons to abandon the B-2.

First of all, the aircraft is really designed to meet any Soviet threat. But the worldwide collapse of the Soviet empire, the retreat from foreign entanglements, and the Kremlin's severe domestic problems make it harder to justify a continued Cold War military buildup.

Rep. Les Aspin, D-Wis., influential chairman of the House Armed Services Committee and a long-time friend of military programs, last year switched from being a B-2 supporter and became an opponent because he could "no longer see any unique and compelling mission" for the aircraft.

A second reason to scrap the B-2 is that the cost may be self-defeating. The United States is faced with a budget crisis and a staggering national debt that Congress refuses to confront, although many members of the House and Senate are growing increasingly uneasy over the situation.

In the past, defense items won easy, almost automatic approval, despite rivers of red ink. Those days are changing, although the glow of victory in the Persian Gulf war has given new life to many Pentagon weapons systems. Still, expenses have to be justifed.

Any nation that spends itself into bankruptcy in the name of military strength is not going to be able to defend itself. Just look at the Soviet Union. The Warsaw Pact has collapsed, communism has been ousted all over eastern Europe, Germany has been reunified, the Soviets are withdrawing aid in Angola and Cuba, and political and economic chaos reign at home.

All of this has happened - not because the Soviets suffered a significant military defeat that sent them into retreat - but because the country's economy is threatening to collapse. The failure of the Soviet economic system led to all the rest.

The United States should draw its own lessons from that debacle. An economically healthy America, free of deficit spending, would be a far stronger nation than one with a vast military apparatus, yet crippled by economic shambles and debt.