IT'S TIME for some energetic white flag waving in the Great War-to-End-All-Wars over Social Security. The partisans on both sides -- loosely organized under the banners of Democrats and Republicans -- have inflicted and suffered their share of political casualties. The leadership is demoralized. The trust funds keep dwindling. As National Social Security Commission Chairman Alan Greenspan warned this past weekend, only a prompt and enduring truce can prevent everyone -- including current Social Security beneficiaries -- from ending up losers.

The difficulty now is that no one wants to take the first step toward a compromise for fear of being riddled by bullets from both sides. Mr. Greenspan, Sens. Robert Dole and John Heinz and other key members of the commission are urging President Reagan and House Speaker O'Neill to help the commission agree on a compromise. But the president feels that's the commission's job. After all, as the president reminded reporters yesterday, the reason he set up the commission in the first place was to defuse the political debate over Social Security.

The commission has done its work to the extent of defining the size of the shortfall faced by Social Security, outlining a series of options and making it clear that both tax hikes and benefit restraints are necessary to solve the problem. But the members of the commission, which includes both Republican and Democratic senators and congressmen, have stopped short of selecting a recommended set of options lest they become sitting ducks for attacks by their colleagues in both parties.

That's a reasonable concern. No matter what the commission agrees to, it won't please those on the one side, who insist that no current or promised benefit shall be compromised, and those on the other, who insist that not a penny more in taxes shall be raised. Because the options are all unattractive, there is no political gain to be had in supporting a solution to Social Security's ills -- real as they are.

On the mere chance, however, that our political leaders might be interested in some statesmanlike behavior, we'll suggest the terms for a possible truce. The Democrats, for their part, could promise never again to mention the Reagan administration's 1981 proposals for sharp reductions in Social Security benefits. These were ill-timed and ill-conceived, to be sure, but they drew attention to an urgent problem. The Republicans, in turn, could swear to forget the political hay made by the Democrats over Social Security in the last election. The Republicans deserved some criticism for loose talk about dismantling the system, but the Democrats misled their constituents by suggesting that no changes were necessary.

Then administration officials and the speaker's men could sit down with the commission members and decide on a balanced set of tax increases and benefit restraints to put Social Security on a safe course for the foreseeable future. No plan can cover every contingency, but the plan should include enough options to offer a reasonable margin of safety. All sides would then agree to push the package to early passage in the next Congress and quit attacking each other.