CONFUSED ABOUT Contadora? Join a growing crowd. Until recently most people felt a Central American peace treaty was a long shot. But an alarm has gone up from within the Reagan administration and, more, from its hard-core constituents that a treaty may soon be signed. What stirs their anxiety is not simply that Congress may take even a flabby treaty as reason to cut off the contras, relieving the Sandinistas of military pressure and allowing them to cheat at will. It is that President Reagan himself, under the baleful influence of some of his closest advisers, may be about to betray the anti-communist faith. This sense of alleged apostasy colors what might otherwise be seen as a round of hardball between the administration's pragmatic and ideological sides.

You do need a conspiratorial turn of mind to understand the flow. Exhibit A is the president's naming of old-line diplomat Philip Habib as his Central America envoy -- an appointment raising the right wing's suspicion that a sellout was being hatched by the ostensibly treaty-crazed State Department and others (Henry Kissinger) thought still to inhabit the place. Exhibit B was the Habib letter saying that aid to the contras would be cut off "from the date of signature" of a Contadora treaty -- although the next paragraph added the condition that "we would not feel politically bound to respect an agreement that Nicaragua was violating." Exhibit C is the departure from the National Security Council staff of Constantine Menges, a high-profile aide whose well-chronicled ups and downs absorb the conservative faithful.

So is there a conspiracy to bring peace, or at least a peace treaty? We need to be shown. Certainly there are conservatives prepared to believe the worst not only about Daniel Ortega, and not only about Democratic liberals, but also about certain members of their own administration. The suspects are thought to lack the proper resolve to unseat the Sandinistas and, in general, to be too ready to point Ronald Reagan toward an accommodation with Moscow.

We think that at most there are people in the administration who are cautiously open to diplomatic opportunities they can imagine but which have not yet materialized. These people do not seem very close to making common cause with the swing bloc in Congress. This bloc doubts, as we do, that aid for the contras can be effectively translated into aid for the democratic cause, and favors building a security fence around Nicaragua and pressing the democratic cause by nonmilitary means. To head off this bloc, the administration has taken to distinguishing between a "good" treaty, which provides for certain and simultaneous democracy in Nicaragua and security in the region, and a "bad" treaty, which leaves the Sandinistas in power.

Such a "bad" treaty, however, may be the best available at this late hour. Pursuit of a "good" treaty is a euphemism for arming the contras, whose failings are all too apparent, and pursuing the course the country is on now -- only in increasing isolation from the countries in the region that are most involved and stand to be most affected by the Nicaraguan outcome. It would be a great mistake to reject our association with them in a negotiating effort now.