American foreign policy will be largely unchanged by the results of this week's presidential election. Continuity is virtually assured. But, in this case, continuity carries with it two uncertainties. President Reagan went in to the campaign with two top foreign policy issues unresolved within his own administration. They remain unresolved in the wake of the election.
One is policy toward Nicaragua. One group of his advisers wants him to seek the complete and decisive overthrow of the Sandinista regime in Nicaragua. Other advisers favor a compromise settlement with that regime on the basis of the proposals of the Contadora group (Mexico, Panama, Colombia, and Venezuela).
The other unresolved issue is over arms control negotiations with the Soviets. There is strong opposition among some senior Pentagon officials to any new limits on the arms race. In the State Department, however, some senior officials think that a reasonable deal could be made.
The President has promised ''serious talks'' on arms control. But there is no agreement yet on whether to seek real agreement with the Soviets, or merely to talk with them in order to pacify public anxieties at home.
There was nothing in the outcome of the elections itself to cause a sudden resolution of these two uncertainties. Overseas friends of the United States will have difficulty understanding how this can be. President Reagan won by the century's biggest majority in the electoral college. Superficially, this would seem to improve his ability to manage foreign policy as he wishes. But the opposition Democratic Party did well at the lower political levels. The Democrats had a net gain of two seats in the Senate, which shares foreign policy responsibility with the President. The Democrats held control of the House of Representatives, which controls spending.
This means that effective foreign policy must continue to be the end product of negotiation and compromise between the President at the White House and the Democrats who control the public purse in the House and will have more influence in the Senate. This is as things have been for the second two years of Mr. Reagan's first term, and will continue to be during the four years ahead.
This is a condition which is rare in modern Western Europe, where a majority in the legislature is usually identical with control of the executive offices. The most recent European parallels would be France before the Revolution or England before Oliver Cromwell. In the US, unlike most other Western democracies , it is possible to have one party hold the White House and the executive authority while the rival party controls the popular branch of the legislature.
The result in the US in the aftermath of Reagan's big popularity victory is that he can still pursue only such foreign policies as the Congress will accept and support. They have been refusing funds to support his counterrevolution in Nicaragua. They will continue to refuse funds for that purpose. And that in turn will continue to make it difficult for Reagan to seek the total overthrow of the Sandinista regime in Nicaragua should he wish to do so.
In policy toward the Soviet Union, Reagan will continue to have to work with a Senate where Republicans are still in control but a probable majority want a more earnest effort to find new accommodations than were made during the past four years.
In other words, Reagan will be under at least as much pressure from Congress as before to refrain from direct military intervention in Central America and to try to reduce the tension in the relationship with the USSR.
He does have Congressional approval to support the existing Duarte government in El Salvador, but he will have a major tussel with Congress if he pushes for the total overthrow of the Sandinista government next door.
There is nothing in the election returns to influence one way or another present US policy toward the Middle East. Reagan pulled the US Marines out of Lebanon in the wake of the failure of the US military excursion into peace-keeping. There is no hint of any serious intention to move back into that still highly unstable situation. The inclination is to wait and see what emerges from Israel's present attempt to manage its catastrophic economic situation (inflation now at roughly 800 percent) and find a way to get its troops out of Lebanon.
The biggest question, of course, is over policy toward the Soviet Union. There are still strong influences in the Republican Party's right wing in favor of waging political and economic warfare against the Soviets rather than seeking accommodations with them. But this course has minimum support in the Congress where the dominant urge is in the contrary direction.
The net effect of the conflict between the urges will mean a continuation of what existed before the election. That was a posture of moving tentatively and cautiously toward an exploration through diplomacy of the possibilities of some new version of crisis management.
There is little basis, if any, for expecting early progress on arms limitations. But arms talks can be a vehicle for groping toward an easier relationship.
There is a clue to watch for. It will tell how serious Reagan is about readiness to seek real accommodations with the Soviets. Progress toward arms talks has been stalemated for some time now in a personalized form.
Richard Perle is assistant secretary of defense for international affairs. He opposes any negotiations with the Soviets. He wants no limits on American rearmament. Richard Burt is assistant secretary of state for European affairs. He believes in exploring for possible accommodations. The battle of ''the two Richards'' has been at the center of the argument over policy toward Moscow.
A report came out of the White House shortly before election day that Brent Scowcroft, former White House national security adviser, would be put in charge of arms control talks, over ''the two Richards'' - in other words, to work out a compromise between them. If that happens, you can assume that Reagan is serious about seeking a genuine dialogue about important matters.
All of which adds up to a negligible change in the US foreign policy posture due to the elections.