Ronald Reagan has put Nicaragua, among other regional disputes, on the summit table. Will Mikhail Gorbachev deal? The president offers Moscow an end to American support of the contras and a role as a guarantor. But Moscow would have to see Nicaragua democratized, de-Sovietized and incorporated into "the family of free nations." It would be relief, all right, but relief spelled o-u-t.

Perhaps at Geneva there will be a saving surprise, an exploration of other terms. If not, a long and grinding conflict promises to become longer and more grinding. You have to be both an optimist and a partisan to believe that either Sandinistas or contras are on the way to a knockout.

The president has yet to deliver visibly on his June pledge to use the renewed contra aid that Congress then voted to move toward negotiation -- and to move the contras themselves toward greater unity and more respect for human rights. The Sandinistas' latest turn of the internal screws, however, can only confirm Congress in its judgment of June that more military pressure is needed to bring the Sandinistas around.

The Sandinistas' crackdown increased the difficulty the internal political opposition was having in holding its own. It also created an opening, which the external opposition could have seized, if it were the strong, united and untarnished collective that its American friends would like it to be. But if the choice is between Sandinista police and unpoliced contras, then the advantage falls by default to the Sandinistas just because they are in power.

The Contadora negotiating process, meanwhile, languishes. On the military side, the Sandinistas favor regional security arrangements but with flimsy provisions for enforcement. Their neighbors and the United States focus on the enforcement.

On the political side, the Sandinistas reject the effort to bind them to the two of the Contadora "21 Objectives" that sanctify pluralism and national reconciliation. They see it, correctly, as an attempt to push them into an accommodation with the U.S.-supported contras, whom they dismiss as bandits, people beyond the political pale.

Yet democracy and reconciliation, besides being intrinsically good, are among the Contadora objectives. Reagan is faulted for wanting to "overthrow the Nicaraguan government," but what he said he wants is to "overthrow the Nicaraguan government, in the sense of changing its structure." Susan Purcell has pointed out in Foreign Affairs magazine that this is precisely what democracy and reconciliation would do.

Here is the pinch: the United States insists that the 21 Objectives be put into effect in a "full and simultaneous" way. It is a popular cry, but it has the effect of linking progress on security issues to the Sandinistas' readiness for political compromise, which means for them perhaps political suicide.

It was not always thus in the Reagan time. The first offer the administration made to Managua, while Alexander Haig was secretary of state, put security issues first. Since 1981, however, the conviction has deepened inside and outside the administration that it is the Marxist essence of the Sandinista regime and not its particular policies that makes it menacing. So the administration has abandoned its first policy of coexistence and containment. It now embraces liberation, either by structural reform (democracy and retaliation) or by the big squeeze (sanctions, contras and the works, up to but, at this point anyway, not including American force).

Since 1981, of course, the contras have come into being and gone into battle and the United States has assumed commitments to them and their cause. urning back the clock to 1981 becomes almost inconceivable.

So here we are. Our conservatives, who are in the saddle, have a policy of pressure in support of insurgents who -- some of them -- are bad apples and who in any event face an uncertain struggle against a nasty but resourceful regime. Our liberals, with exceptions, don't like the Sandinistas a whole lot more than they like the contras. They're for freedom but they're against intervention, which leaves them wringing their hands and wishing that it were plausible to pass the buck to Contadora.

Many Americans are wrung out or bored by Central America and even those who still acknowledge that something important is at stake there feel we really ought to be focusing on the great problems elsewhere in the hemisphere.

In this dismal swamp, the sensible thing is for President Reagan to get himself a new lawyer for Central America -- someone senior, detached and respected who knows the Latin terrain and, most important, who knows how to serve presidents: Sol Linowitz.