THE United States faces a clear choice in Central America. The Reagan administration can - and, we think, should - support the Arias plan now accepted by Nicaragua and four of its neighbors. Or the White House can continue to find subtle ways to pick apart the regional peace approach. For the Latin plan to succeed, strong US support is essential. If Washington does not want an agreement, there probably won't be one.
Obviously the administration would have preferred the tighter timetable and fuller safeguards of its own, newer Reagan-Wright plan. But the ambivalent US stance taken toward the Arias substitute preferred by Central Americans effectively sabotages it. The confusion shows up in several ways.
In its plan, the administration promised to abandon its anti-Sandinista rhetoric and to stop pushing for more aid to Nicaragua's contra rebels during early negotiations. Yet most of the talk coming from the White House in the last week centers on US distrust of the Sandinistas and the need to continue contra aid at all costs.
US diplomats from the five pertinent Central American nations were called home this week and told of administration suspicions that the Sandinistas will not fulfill their part of the democratic bargain.
The sudden resignation late last week of Central American peace envoy Philip Habib, said to favor a warmer embrace for the Arias plan, is yet another open sign of the administration's ongoing internal struggle.
At the heart of the administration's waffling is the wish by conservatives to hang on to the contra aid weapon as a kind of security blanket in case the Sandinistas don't live up to their promises.
But Managua can't be put to any honest test of its pledge unless the aid stops; the Sandinista excuse has always been that civil war keeps them from the luxury of allowing democratic freedoms.
Four of Nicaragua's neighbors in the region have agreed to the test. They don't particularly like the Sandinistas, and these are the countries that will pay the price if the guess is wrong. Yet they say, via the accord, that they can live side by side with Managua without a political change of regime there. These neighbors see a more open society in Nicaragua, more than stepped-up contra aid and military forces, as the key to their security. But they do not demand that Managua change into a democracy as a condition.
The US must now face that question and give it an honest answer. Do its interests really require a democratic government in Nicaragua? If the US goal is nothing short of a change of government, that question should be put to a clear vote in Congress. This alternative might imply marching in with US troops rather than continuation of a proxy civil war waged by Nicaraguans.
But isn't the real concern the move toward a closed totalitarian society rather than an undemocratic government per se? To thwart the whole peace effort begun in Guatemala because it does not ensure a democratic government in Managua is unwise. If Nicaragua skips out on its promises, other pressures apart from contra aid are available; these include economic sanctions, which could attract broader support on both legal and moral grounds.
Washington can show that support for the Arias plan by an abrupt drop for the moment of all the talk about contra aid. Mr. Habib should be promptly replaced with someone of the stature of a Brent Scowcroft, Cyrus Vance, or Sol Linowitz. The US could benefit by sitting down with Managua in bilateral talks, so long urged by the Contadora nations, to frankly discuss plans, concerns, and intentions. And to make Latin nations less vulnerable to totalitarian governments and guerrilla forces in the future, the United States should consider a long-term strategy of fostering much-needed economic and social development through a stronger aid program.