THE REAGAN administration professes an interest in negotiating its differences with the Sandinista regime in Nicaragua but, meanwhile, sponsors a ragged little secret war out of Honduras against it. Theoretically, it is possible that the secret war, on which Newsweek offers fresh details, will induce Managua to bend at the negotiating table. Realistically, the prospect looks remote.

The method to the administration's covert plan is not apparent. No claim is made that it can topple the Sandinista regime, and there is no indication yet that it can destabilize it, either. In fact, in Washington there is no consensus on the crucial point of whether the operation is meant to produce a political settlement or a military showdown. The impression conveyed is that the administration would simply like to knock off a pesky Marxist-oriented regime in the American backyard.

The CIA is going about it, however, like an amateur. Not only are a great many of "our" Nicaraguans Somocistas, the men of the late, reviled dictator -- the good anti-Sandinista Nicaraguans are staying at arm's length. The Nicaraguan exiles being sponsored by the United States are operating in the countryside, where Sandinista land reform has drawn many campesinos to the regime. In brief, we are sending the wrong guerrilla fish into a rather inhospitable sea.

In so doing, we are embarrassing the democratic, largely urban-based elements who are our natural friends in Nicaragua, inviting the Sandinistas to come on as patriots in the old anti-Yankee mold, and abandoning the high ground on which we ask other countries to condemn Nicaragua's support of insurgents in El Salvador and Honduras.

Is there a way for the people supporting pluralism and democracy in Nicaragua to prevail? No struggle against an armed Cuban-and Soviet-backed dictatorship is easy. But democratic elements are still vigorous in Nicaragua. They have able and uncompromised leaders. Since Moscow shows no signs of taking on a second "Cuba," the country's economic crisis gives an opening to those who want to keep Nicaragua close to the West.

The real question is whether the democrats would fare better in a context of American-Nicaraguan tension or of some American-Nicaraguan relaxation. There is no guarantee that a more moderate American policy would elicit a relenting on the Nicaraguan side. The current policy, however, appears to be taking the United States only into deeper water.