A MONTH AGO, when debate over Social Security was nearing its pre-election low, a stranger to the ways of American politics would have concluded that chances for a reasonable solution of Social Security's troubles were nil. With the drafting of a compromise plan by a national advisory commission last weekend, the prospects for a sensible compromise seem remarkably brighter.

In this case, a possibility for retreat from the excesses of campaign promises was made available by the existence of a well-respected advisory commission whose members had been selected over a year ago by leaders of both parties. The commission did not reach a final decision on recommendations. But leaders of the group, working long hours in seclusion, managed to put together the outlines of a plan that would address both the short-term and long-term problems of Social Security.

The compromise hasn't been agreed to by all the members, and it is neither perfect nor complete. The rescue package for the next several years relies too heavily on payroll tax step-ups -- thus driving up labor costs and increasing the tax system's tilt against low- and middle-income workers. It also ignores some sensible reforms, such as covering all state and local workers and making better-off retirees pay income taxes on the part of their benefits that they didn't contribute. Nor are the proposals to ensure long-term solvency and provide protection against cyclical slumps fully specified. Nonetheless the commission has established the basis for a reasonable compromise when Congress takes up the matter early next year.

What is most notable about the plan, however, is what is not in it. While the commission chose to take a conservative view of the economy's future path, it was still able to lay out a plan to finance Social Security for the next 75 years that avoided the Draconian solutions that have been talked about in recent months. There is no retreat to voluntary planning for old age, no means-testing of benefits, no postponement of the retirement age. Current beneficiaries would face a one-time, three-month delay in cost-of-living adjustments, but no other changes. Beneficiaries retiring after the year 2020 might not receive the full improvement in benefits currently built into the system, but even that would depend upon conditions at that time.

The immense significance of the commission's work is that it lays out a limited set of measures that would put the system on a sound basis without changing the system in any important way or destroying the economy or threatening the security of either present or future retirees. This should come as a relief to the millions of Americans who may have been misled by recent political argument into believing that our most important social system is about to come crashing down on either this generation or future generations of retirees