It's easy to be enthusiastic about the new plan unveiled this week by five Central American presidents for bringing peace and freedom to their troubled region.

All that's required to generate rave reviews for the plan produced by the presidents of Nicaragua, El Salvador, Honduras, Guatemala and Costa Rica is an incredibly short memory.In essence, the plan calls for the five heads of state to devise, within 90 days, ways of disarming and disbanding the 11,000 anti-Communist Nicaraguan rebels camped in neighboring Honduras and sending them home or to some other countries.

In return, the dictatorial regime of President Daniel Ortega promises to permit free and fair elections next February, after giving all political parties theaccess his opponents have long been denied to the press, television and radio.

To cheer this plan, one must merely forget Ortega's long record of promising democratic reforms in Nicaragua and then breaking his vows.

Forget that the Contra rebels were never consulted before this week's plan was produced. Forget that the plan contains no detailed schedule of deadlines for holding Ortega's Sandinista regime to its latest commitments.

Forget, too, that Ortega's brother Humberto, a member of the Sandinista clique, once admitted: "Ours are elections to advance revolutionary power, not to raffle off power."

Having said all this, the fact remains that there's not much that Washington or the Contras can do to make Ortega keep his new promises as long as the rebels are so weak and as long as the U.S. Congress keeps denying them military aid. Consequently there's little the United States can do except to explore this week's proposal.

Meanwhile, at least the United States is still providing the Contras with food, medicine, clothes and other non-military necessities. Congress must not assume it can start cutting back on such humanitarian aid just because another new peace plan for Nicaragua has come along.