AFTER MORE than two years of work, members of the Senate subcommittee on civil service have come up with a design for a new federal pension system. It's a good plan -- perhaps the best one possible under the fiscal and political conditions likely to prevail for a long time to come. It needs and deserves strong bipartisan support.

Young people considering government service as a career now have to make that choice without knowing what kind of a pension might be in store for them. That's because Congress decided two years ago to cover new government workers under Social Security, but never got around to redesigning the federal pension system to go along with that decision. Part of that delay was unavoidable, given the complexity of designing a system that won't be paying out benefits until well into the next century. But Congress has also been wary of moving forward on a plan for fear of offending the powerful civil service lobbies.

No pension plan with any reasonable price tag can satisfy every interest. But the Senate committee plan -- the handiwork of Sens. Ted Stevens, Tom Eagleton, William Roth and others -- strikes a reasonable balance between the interests of long- term civil servants, those who move in and out of government and the taxpayers who must pay a substantial part of the system's cost.

On top of basic Social Security benefits the plan would add two tiers -- a plan guaranteeing retired workers a pension equal to a specified proportion of their prior earnings, and a voluntary "thrift" plan allowing workers to have their savings matched by their agencies and given special tax treatment. No worker contributions would be required except regular Social Security taxes.

The new system would actually improve benefits for workers retiring at age 62 and older, those with relatively low salaries and those who move in and out of government. The retrenchments -- and long- run savings for the taxpayers -- would come in reduced benefits for early retirees and less than full inflation adjustment for second-tier benefits. Naturally government unions and retiree groups will fight any losses. But there is widespread feeling that government pensions are now too generous for early retirees and that the long-run costs of continuing the current system are not supportable.

There is room for compromise within the general framework of the committee plan. But the overall design -- the balancing of interests, the choice of incentives -- seems about right. Of course federal workers' unions would like to make the plan more generous. But they should remember that the White House, which can surely block any plan it can't tolerate, will be pressing for a more stringent one. Without solid bipartisan support for the committee plan, the final outcome may be far less favorable for future government workers.