OMINOUS SIGNS in El Salvador suggest that the guerrillas are planning to uncork another military offensive. The military pieces are being put into place, including the return of new troops trained in Cuba and the deployment of the Cuban-provided surface-to-air missiles with which the insurgents might hope to offset the armed forces' American-supplied air power. Political preparations include a toughening of the FMLN's position in the peace talks going on under United Nations mediation. For instance, the FMLN now makes the outlandish demand for sweeping changes in the armed forces, such as replacement of all colonels and generals, before a truce. The FMLN declares that official "intransigence" makes "a resurgence of military action ... almost inevitable."

Why would the guerrillas want to put at risk the immense gains that could flow from the continuation of peace talks? Why would they see advantage in breaking their commitment to negotiations, thrusting the 11-year civil war back into high gear and taking on the blame for a new surge in killing? Perhaps the FMLN thinks that Americans are so engrossed by the Iraq crisis that another round of savagery in El Salvador wouldn't be noticed. The guerrillas might also be thinking that in their last offensive, in November, they came out pretty well: they showed their muscle, brought the government to the table and found that Congress, far from penalizing them for starting the offensive, instead halved aid to the government for a massacre -- the killing of the Jesuits -- that army officers perpetrated in the heat of battle.

El Salvador is a fading political cause in the United States. With the changes in Managua and Moscow, a vote against aid to Salvador imperiling the government can no longer be depicted as a contribution to a regional or global threat. What passion on the issue remains in Washington centers in the ranks of congressional Democrats whose priority is to see justice done in the case of the Jesuits. They have a worthy and necessary cause. They also have a responsibility to take a broad view and to convey unequivocally to the Salvadoran left that the onus for an offensive will fall entirely on it.