THERE IS A widespread sense that the crisis in

Central America is intensifying. Actually, two different things are happening. The war is deepening and spreading, and the threat of still a wider war is growing. As a result, however, the search for peace is getting more serious too. Those who would steer the process to a good end need to take account of both currents.

A large group in Congress is appalled to see President Reagan expanding the Pentagon and CIA roles, and wants to cut military aid to El Salvador and halt support of the counter-Sandinista insurgency in Nicaragua. The group feels frustrated but, partly in response to it, Mr. Reagan has expanded his diplomacy, dispatching Richard Stone to make contact with the Salvadoran left and opening up tentatively to the peace efforts of the Latin Contadora group.

Nor is the effect of the Reagan approach limited to the stirring of congressional opposition, which in turn stirs official interest in negotiation. The Sandinistas have now endorsed the American call for region-wide rather than state-to-state negotiations. One agenda point they propose--a breakthrough-- would require them as well as Washington to stop sending arms to El Salvador.

It is tempting to take up items one by one and strictly in their own terms, outside the larger context in which they rest. If we were dealing that way with CIA sponsorship of armed intervention in Nicaragua--which this newspaper has opposed from the start--we would promptly end it. We think now, however, that the record shows that the intervention has helped produce Managua's apparent shift on negotiations. The question that has to be tackled is how to end the intervention in a way that promotes talks.

The trouble with Congress' easing the pressure on Ronald Reagan, however, is that he may feel free to go his own way. Here is his true flaw: he has failed to show reasonable people, in this country and abroad, that he is content to pursue reasonable goals. Therefore they hesitate to trust him, even when they support much of what is trying to do.

The other day, for example, he reiterated that for him to let up on them, the Sandinistas must not only leave their neighbors alone but also broaden the regime. Respect for neighbors is necessary and reasonable. Broadening the regime is desirable but unreasonable as a condition for ending military intervention. Where else is the United States sponsoring an invasion for that end? None of the Latin nations whose help is essential to him, including the Contadora four, will follow him down that path.

The four--Mexico, Venezuela, Colombia, Panama --are a wise president's dream team: friendly Latins, democrats or heading that way, aching to help for their own urgent reasons. Able to bring to bear only persuasion and consultation, however, they can do nothing that the local parties and most of all the United States, the dominant force, do not permit them to do. Much in Managua's new statement is unacceptable, but a hint of an opening is there. For the United States to take advantage of it, the president must show clarity in ends and restraint in means in a measure that has eluded him so far.