MEMBERS OF CONGRESS will be welcomed back this week by, among other things, fervent appeals for an override of President Carter's order limiting federal civil-service and military pay increases to 5.5 percent. The cries from federal employee unions and their supporters, including Rep. Herbert E. Harris (D-Va.), will be especially plaintive because inflation is high and on the rise. Mr. Carter has approved less than two-thrids of the 8.4 percent hike that, according to his advisers, would be required to keep federal pay in step with increases in private industry. With inflation accelerating toward the 10 percent range, the squeeze already felt by federal workers and their families is bound to get worse.

In part just because the prospect are not pretty, we think President Carter is right. He announced last spring that he intended to hold federal increases down to 5.5 percent to set an example for businesses, unions and state and local governments. The aim, of course, is to keep pay level from spiraling upward even more rapidly and inexorably. And the fact that inflationary pressures have gotten worse makes federal restraint even more vital now. If Mr. Carter had abandoned his ground, he would have lost virtually all hope of exerting useful leverage on other economic sectors - or reassuring foreign governments about the dollar's state. True, if Mr. Carter had never mentioned a specific limit last spring, something more than 5.5 percent might seem justifiable now. Having drawn that line, however, he had to hold it - or send the wrong signals to everybody else.

Serving as an example is not much compensation for the public servants whose pay levels are at stake. Even the unique benefits of federal service - starting with job security and the exemption from Social Security taxes - may not seem like much comfort to a family whose grocery bills are outpacing its income. But that inflationary tradmill can't be stopped if everyone waits for someone else to get off first. That's the hard truth that Rep. Harris, for one, seems to have forgotten. His campaign flyers emphasize his efforts to fight inflation - but he has abandoned the cause now that it's coming close to home. President Carter has taken a far better stand. We hope that Congress wil support him.