By all rights the mood of Congress ought to be grim.

There are war prospects in the Persian Gulf, a worsening budget deficit and possible recession at home. The mail has turned ugly over the savings-and-loan scandal.And a new national poll shows a growing tendency of more Americans to disapprove than approve of the way Congress is doing its job.

A significant minority - 42 percent - even thinks that at least half the members of Congress are corrupt.

For all that, few of the lawmakers seem to be really worried.

They still have plenty of support, you see, where it counts the most - among the nation's assorted special interests.

According to the Federal Elections Commission, organized political action committees (PACs) gave $94 million to congressional campaigns through June 30.

As usual, incumbents got the lion's share, a record $79 million, compared to only $6.5 million for their challengers and $8.1 million to candidates for open seats.

That's nearly a third of all the money - $279 million - that candidates have collected.

The PACs' bias toward incumbents goes far to explain why the face of Congress changes so slowly, and why there is no serious expectation that Congress will actually ban PAC contributions, as the Senate has voted to do, or even restrict them, as the House purports to favor.

At least 98 House members have already received more from PACs than the $275,000 that would be allowed under the House version of campaign finance reform legislation.

It's the rare lawmaker whose voting record doesn't betray the influence of the PAC contributions.

The American Medical Association, for example, has already donated more than $1.1 million this year to congressional campaigns. It is no coincidence that so few incumbents have come out in favor of national health insurance.