Our debate over El Salvador has been badly skewed by the requirement of the law that every six months the president, to continue aid, must certify that the Salvadoran government has met certain standards of rectitude with regard to the conduct of its internal affairs.

No president will want to risk letting a "totalitarian Marxist regime" take over, as our ambassador there has just put it. Nor is any post-Vietnam Congress likely to go beyond adding hard-to-enforce conditions and to take upon itself the responsibility for pulling the plug. So this time around, as earlier, the president will give El Salvador a stamp of approval and the critics will anguish, as, I believe, they both are right to do. No one will be happy, but life will go on.

The trouble is that death will also go on. For the larger truth of the situation is that no one has a good idea for ending the war. The Salvadoran government's formula for a settlement and the guerrillas' formula are mutually exclusive. Each side can get enough recruits and arms to fight on indefinitely. The glory and the curse of Salvadoran society is that it is resilient enough to withstand a brutal protracted struggle of a sort that surely would have broken most other lands.

What this means for the United States is that it can perhaps count on accomplishing half its mission, to prevent its tigers in El Salvador from losing, but not the other half, to bring the Salvadoran government to something that might be called winning or prevailing or being able finally to stand on its own.

Half is better than none, but half is not good enough. In a context where the government and guerrillas continue to lay waste the country and its people, a stalemate becomes a defeat as time goes on. A condition that is justifiable as the result of a two-year investment sours in three or four. Meanwhile, the collateral costs mount--the spreading of the war in Central America, the spectacle of the dogged but ineffective giant, the political friction at home.

So it is time for a new American policy, one that anticipates events, gets out ahead of the curve. Yet it is foolish to suggest that President Reagan simply embrace the logic of the human rights groups and in effect throw in the towel: foolish because he is unlikely to do it, foolish because the policy is not sound. Reagan needs to be shown an alternative way to serve a definition of the American interest that he finds acceptable.

Why not borrow in El Salvador from the approach the Reagan administration is applying in the Middle East?

Last Sept. 1 Reagan stopped defining the Mideast simply as a scene in which to uphold the Western side of an East-West confrontation. Instead, he went to the heart of one key source of instability in the area, undertaking to resolve the Israeli-Palestinian dispute and to serve the American interest in Israel's security by outlining the terms of a fair settlement and then starting to push for it.

Why not try, in El Salvador, to resolve the civil war and serve the American interest in the government's security by outlining the terms of a fair settlement and starting to push for it?

The prospective terms:

1) A cease-fire to lower the temperature.

2) Amnesty for everyone, no matter what horrible things have been done.

3) Equal legitimacy and access for every political and political/military group.

4) A welcome for all invited observers, peace-keepers and hand-holders.

5) A pledge by outsiders to respect the results.

But, you will object, this proposal skips right over the core issue, political power. You bet it does. The United States has no business dictating in that area. That's the great flaw of our current policy: by supporting the Salvadoran government's demand to reserve power to the outcome of an electoral process of its own devising, we are dictating. The guerrillas' demand, to allot power by a negotiation to groups that have not electorally earned it, also amounts to dictating and is no less objectionable.

The wiser course is for the United States to hold the political ring while the Salvadorans work out what they can. On such a platform Washington could surely improve its chances of drawing the cooperation of key Latin countries--Mexico, Venezuela--that are now going their own separate (and ineffective) way.

I am aware how easy it is to pick flaws in a proposal like this one. But it does seem to me to meet the two tests that matter most: it respects the basic principle of Salvadoran choice to which Reagan and Jimmy Carter have dedicated American policy in El Salvador, and it promises an end to the war.