As the National Commission on Social Security Reform has been moving toward its Dec. 31 expiration date with no bipartisan agreement in sight, there have been repeated erroneous assertions that neither Democrats nor Republicans on the commission dared put forward a proposal, for fear of having it shot down. From this pad of false assertion have been launched appeals for a "truce" between partisans on the commission and for a "summit meeting" of President Reagan and Speaker O'Neill, the leaders of their respective parties. Fortunately, this notion was very quickly shot down by both leaders, who understand that summitry is only possible if a solid base for it has been established by arduous effort at lower levels.

Unfortunately, however, the perception remains that Democrats and Republicans on the commission have been equally laggard in volunteering solutions to Social Security's problems. All but forgotten in the past few weeks is the fact, reported by at least some media at the time, that Democratic members offered a compromise proposal at the meeting of the commission a month ago. This proposal reflected concessions by each of the Democrats from previous positions, in the interest of possible bipartisan agreement on how to ensure the solvency of Social Security. The proposal, with indications of support from Speaker O'Neill, was conveyed to the Republican commission members and, through them, to the White House. But to date, there has been no response to it, beyond a handful of comments from individual Republican-appointed commission members--no discussion of it by the commission, and no counterproposal from the other 10 commission members as a group. Given these facts, I would not predict how many Democrats, including myself, might still feel bound by the proposal.

I, for one, believe that Democrats and Republicans alike have a responsibility to ensure that whatever steps are taken to help Social Security as a system, they do not violate this nation's nearly half-century-old moral compact with Social Security beneficiaries, who now number 36 million. For some reason, those of us who have advocated solutions that would maintain the current level of social- insurance protection have been accused of demagoguery. Surely there is room for honest differences in approach; are those who advocate benefit cuts rather than other approaches necessarily more courageous or correct? Certainly the recent election showed that the citizens of the country wanted more representatives in Congress who are committed to maintaining the promised, cost-related level of Social Security benefits. (If Republicans are feeling singed by the results of the November election, they should look toward the White House to find the firebug.)

I am not saying that some concessions will not be necessary. But I would emphasize that the problems of Social Security are not endemic to that system. All the system does is try to keep the meager benefits of older Americans -- an average $5,000 a year, barely above the poverty line for individuals -- apace of the rising cost of living. Can we as a nation do any less for our senior citizens -- or for the younger people of today who are paying taxes into the system and have a right to expect the same benefits when their time for retirement comes?

The immediate problems of Social Security are most directly related to the skyrocketing unemployment of the past two years, which not only has robbed millions of their livelihoods but also has deprived the Social Security fund of the payroll taxes it needs to meet its obligations. Thus, the single most important thing the president could do to save Social Security would be to reverse his disastrous economic policy and steer full speed ahead toward full employment.

Unemployment is not, of course, anything the Social Security Reform Commission can do anything about. Indeed, the commission has committed itself to a very pessimistic projection of what the economy will be like for the remainder of this decade, with continuing high unemployment, and has determined to cover a possible shortfall of $150 billion to $200 billion. Most Democrats regard as quite reasonable a middle-of-the-road projection of a need for about $60 billion for the rest of the decade. (Ironically, if unemployment could be reduced to and kept at 5 percent through this decade, the Social Security fund would gain $46 billion, more than three-fourths of the projected $60 billion shortfall.) Further, we think projections beyond 50 years are pure speculation. But we are going along with the more pessimistic projections--not out of an expectation of disaster, but rather out of an abundance of prudence and in a spirit of compromise.

The Social Security Reform Commission still has a little time to develop a bipartisan approach to the problems of Social Security. I believe Chairman Alan Greenspan has been sincerely trying to bridge the differences among the Republican members of the commission, and between them and the White House. He may yet be able to do that, and to effect an agreement that encompasses the entire commission.

But whether or not a bipartisan agreement emerges from the commission, I know that the Democrats who control the House of Representatives, where legislation on this issue must originate, are committed to developing a prompt and fair solution for the problems of Social Security.