CENTRAL AMERICA, today, is proving an old adage: In diplomacy as in politics, timing is crucial. President Reagan recently joined with House Speaker Jim Wright to propose a new peace plan. Five Central American Presidents were thus goaded into signing a rival plan of their own - suddenly creating new prospects for peace. The Reagan administration must finally decide what are the irreducible US interests in the region.
Some observers see the Reagan-Wright plan as designed to prove that the Sandinista regime in Nicaragua would not negotiate, thereby paving the way to secure more congressional funding for the contras. That may have been the administration's game plan.
Nevertheless, Mr. Reagan did reach out to critics in Congress and the Democratic Party. In action if not in intent, he took a first step in rebuilding trust and cooperation with Congress; he calls it ``the eventual blessing in disguise to come out of the Iran-contra mess.''
If this first step is not the last and Reagan follows the instincts that led him to work with Mr. Wright, it may now be possible to spare the next president and the 101st Congress the legacy of a festering problem.
That will not happen, however, unless the President resists his critics - his own political allies - who feel betrayed by the document signed in Guatemala. That plan, devised by Costa Rica's President, Oscar Arias S'anchez, provides no guarantee that the Sandinista regime will permit democracy. Aid to the contras must stop by Nov. 7, and the United States must abandon support bases in Honduras. Yet progress toward pluralism in Nicaragua will be far harder to discern.
In the weeks ahead, the comandantes in Nicaragua are unlikely to do more than make a bow toward pluralism to get a cease-fire and a halt to contra activity. But political support for the contras is moribund in Congress and in the US at large. Under pressure, Congress would perhaps permit a trickle of new money to avoid a charge of ``losing'' Nicaragua. Yet even before the Iran-contra hearings, it was clear that there would never be enough money for the contras to overthrow the Sandinistas.
The policy struggle within the administration reflects the confusion of purpose behind arming the contras. Indeed, right-wing critics of Reagan's initiative with Congress have it backwards when they talk of his ``Bay of Pigs.'' That policy failure in 1961 was a romantic exercise in relying on the wrong people to do too much with too little. The Reagan-Wright plan was the first step in waking up from a similar dream: that the contras could prove victorious in the Nicaraguan jungles.
Realism also means understanding that the declared purpose of forcing pluralism on the Sandinistas can only be achieved by sacrificing US lives. Few people in the US are willing to pay that price for democracy in Nicaragua.
By contrast, the contras seem to have been instrumental in achieving another, less noticed goal of US policy: acceptance by Nicaragua of a peace process that can be used to reduce direct security threats in the region. This goal, less ambitious than a Sandinista overthrow, has the virtue of broad support across the US political spectrum.
There is consensus in opposing any more Soviet bases in the hemisphere, beyond Cuba, or any Soviet nuclear weapons. There is strong support - in Congress and the nation - for gaining limits on Nicaragua's armed forces and weapons supply, and for the removal of Soviet and Cuban military bases and advisers. If acrimony over the contras can be reduced, then unity of purpose can be reaffirmed on these key objectives.
The Arias plan is weak in dealing with US security concerns and is likely to prove deficient in moving Nicaragua toward democracy. From a regional-security standpoint, however, it is far more important in negotiations to put US chips on concrete security measures than on efforts to reform Nicaragua's political system.
US critics of the new diplomacy may be right in arguing that, in its current form, the Sandinista regime will always pose a threat to its neighbors. Yet that is no argument for giving the contras one more chance. Their notorious failure to ignite popular support in Nicaragua argues for trying something else. Indeed, the Arias plan, which enjoys widespread backing within the region, can be a more realistic instrument for pursuing democracy in Nicaragua over the long term than the contras have ever been. Yet that would also depend on a continuing US role and major infusions of development aid to the region.
As the bargaining begins, Reagan must end the polarization within his administration and decide the bottom-line goal for US policy in Central America. Yet if he puts US security interests ahead of ambitions for Nicaragua's political system, he stands a chance of being effective, both in Central America and at home. That is a legacy worth leaving to his successor.
Robert E. Hunter, senior fellow at the Center for Strategic and International Studies, was a lead consultant to the National Bipartisan Commission on Central America (the Kissinger Commission).