THE HOUSE VOTE on the $12,900 congressional pay raise this week is doubly awkward because it comes four months late.However risky and uncomfortable a roll-call vote in February would have been, the leadership's decision to duck and let the increase take effect automatically has fed public suspicions that its action was somehow underhanded and that the pay raise is unwarranted. Thus there is now substantial sentiment for rescinding the raise. In our view, that would be a serious mistake. It would make Congress look even more cowardly and would deny members an increase that we think is justified.

A salary of $57,500 may sound like a lot, but it is not too much these days for full-time work at a job that, after all, involve passing judgment on every aspect of national policy. As John Gardner argues on the opposite page today, an adequate or even generous salary is vital to encourage more first-rate people to serve in Congress. Moreover, this particular raise was an especially good bargain for the taxpayers because it spurred both houses to adopt tough financial-disclosure rules and strict curbs on outside earnings and activites. In effect, members agreed to give up some outside payoffs in exchange for higher pay. Surely that's a constructive trade.

Some legislators, out of personal conviction or under political stress, want to forego the raise or donate it to charity. That's fine. They can do that, and square themselves with disgruntled constituents if that's their problem, without denying the raise to those who want it and need it and are prepared to stare down the voters. To roll back everybody's increase, however, could be positively harmful if it became a justification for undoing the ethics codes. It could also cause real financial strains for legislators of modest means, especially those who have served for years at lower salaries.

Moreover, the public-relations effects of a retreat are not likely to be as helpful as some members hope. A cutback would be seen as an attempt at atonement, like pleading guilty to a bum rap. It would thus confirm the widespread impression that Congress has been trying to sneak one over from the start. That impression will be harder to avoid, by the way, if the House should vote a pay cut - and in the same bill approve a new employee parking lot and the outrageous, unnecessary extension of the West Front of the Capitol. Nothing would tell voters more clearly that congressional self-sacrifice is a sham.

The House should be mature enough to face the pay issue squarely and affirm the raise. Out of nervousness, however, the House leadership is trying to package the test vote as one on cutting not only congressional salaries but those of top executive-branch officials as well. That harks back to the bad old days when executive pay scales were arbitrarily held down for years by Congress's refusal to vote an increase for itself. Of course a rollback would be immensely disruptive and unfair to high-level federal employees. This is just one more reason for the House to appropriate the money for the government-wide increases, which took effect, properly, last spring.