REMEMBER El Salvador? It's the little country in Central America that two wars ago--before the Falklands and Lebanon--was at the hot center of American foreign policy debate. The political calendar is reviving the issue: it's aid time. The president must certify by the end of July that El Salvador is making progress on human rights and reforms, and Congress must then decide on amounts and terms.

Let us go to the particular issue, land reform, that events have made a fair surrogate for other issues of American concern. When last heard from, land reform was being done in by the assembly elected in March, and an aroused Congress was threatening to cut aid. And now?

It helps to ask why the new Salvadoran assembly started hacking at phase three of a reform whose first phase (taking over big farms) remains intact and whose second phase (medium farms) was stillborn under the previous Duarte government for lack of funds. Phase three was to give "land to the tillers"--pieces of land under 17 acres to renters and sharecroppers. The Duarte government, however, finding a huge hitch, discreetly suspended "Decree 207": farmers wouldn't work for wages, waiting to rent so they could take title, and owners wouldn't rent, knowing they would lose title, and as a result production plummeted.

The new post-election president, the pro-reform Alvaro Magana, thought to slip this production noose by formally suspending 207 for one crop cycle on land for cotton and sugar--export crops. The anti-reform assembly, however, mischievously added cattle and cereal grains land. Seeing reform falter, Congress took aid knife in hand.

What Congress missed is the sequel: Salvadorans reacted strongly, some in anger, some in relief, to the aid threat. Both the law and administrative procedure were clarified and titles are again being distributed, though performance is erratic. The basic point remains that the reform is now accepted and newly protected not just by the executive branch, which was put in place by the pro-reform army leadership, but also by the same assembly that had earlier impeded progress.

There is too much blood in El Salvador, and too much backwardness. There are good people in and around the government, and some weak and corrupt people. Anyone hunting for evidence on which to flunk El Salvador can easily find it. It seems to us vital, however, to try to understand how tough it is for a poor, underdeveloped country racked by war and revolution to demonstrate to foreign satisfaction that it is modernizing with sufficient speed. Success cannot be guaranteed for the American effort to nourish democracy and reform in El Salvador. Failure can. All you need to do to guarantee failure is pull the plug on aid.