To protect them FROM the ravages of inflation, Congress three year ago promised to give U.S. retirees regular cost-of-living adjustments every six months. Forever. Forever didn't last very long.

Right now Congress is in the process of breaking, its 3-year-old pledge BECAUSE of the ravages of inflation.

The House this week okayed a proposal from its budget committee. It would eliminte one of the two cost-of-living raises retirees now get each year. Instead of the two inflation raises promised, retirees would be limited to a single cost-of-living adjustment each year. That change from March and September adjustments to a one-shot boost each July will cost the typical retiree about $1 per day in future benefits.

The Senate is expected to approve a similar one-shot cost-of-living resolution from its budget committee next week.

The two committees charged with monitoring federal pension benefits -- the Senate Governmental Affairs Committee and the House Post Office-Civil Service Committee -- will have little choice but to approve the one-shot cost-of-living. Unless somebody can pull a legislative rabbit out of the hat (and rabbits are in short supply this year) the two cost-of-living raises will become a single raise.

The argument against the twice yearly adjustments is that they cost too much now that inflation is approaching 20 percent a year. Retirees argue that because inflation is bad, they need the frequent adjustments now more than ever.

Retiree groups, military groups, federal and postal unions oppose the cost-of-living cutback, naturally. But they are fighting an uphill battle in a Congress that has preelection jitters, and wants to present the voters a balanced budget -- or at least the promise of one -- before we all go into our respective voting booths this November.

Once the single cost-of-living raise becomes law, insiders expect the next step -- probably next year -- will be for Congress to change the Consumer Price Index formula, to further whittle back inflation-triggered raises. There is a good chance that somebody will suggest that federal and military retirees not get full cost-of-living raises in future, rather that the boosts be "capped" at a certain percentage, no matter what the actual cost-of-living.

Because the White House supports the idea of single raise, Carter aides anticipate some backlash from the federal-military-retirees voter bloc. That is about 8 million people.

But Carter strategists are also counting on Ronald Reagan being the Republican nominee. They believe that, no matter how ticked off the government crowd is, it will finally decide that Carter is better than Reagan. Maybe so. But read the next item.