Baker Warns Sandinistas on Behavior : Nicaragua: Says an election victory alone would not normalize relations. Managua must end support for El Salvador rebels.

Secretary of State James A. Baker III said today that even if Nicaragua’s ruling Sandinistas win Sunday’s election, the United States will improve ties with them only after a sustained period of “good behavior.”

Testifying to the House Foreign Affairs Committee, Baker said the United States will not necessarily accept the election as fair, even if neutral observers such as former President Jimmy Carter and former Atty. Gen. Elliot Richardson certify the results.

“The United States must reserve unto itself the right to make its own judgment about whether that election is free and fair,” Baker said.

“If you’re going to assume there is a Sandinista victory . . . it’s very important before we talk about normalizing relations with that government that we see a sustained period of good behavior in terms of refraining from subverting their neighbors,” he said.

Washington has repeatedly charged that the Managua government is shipping arms to left-wing insurgents fighting the U.S.-backed government in El Salvador.

Baker said the election campaign had not been totally clean and opposition candidates and poll-watchers had been intimidated and their funds blocked.

In his prepared statement to the committee, Baker hailed what he said were major U.S. foreign policy triumphs in the last two weeks.

“These last two weeks have registered major advances in the President’s foreign policy,” he said.

“We are measurably closer today to a Europe whole and free. . . . We have taken important steps toward controlling chemical weapons and a START (strategic arms reduction) treaty. And working with our allies, we are also moving forward in the war against drugs.”

Baker was able to bask in the unanimous praise of committee members at his recent achievements in arms control--an unusual occurrence for a secretary of state testifying before Congress.

In his wide-ranging review, Baker insisted that the “two plus four” forum worked out last week to handle security aspects of German reunification adequately protected the interests of Germany’s neighbors not included in the six.

The plan envisages the foreign ministers of East and West Germany, plus Britain, France, the Soviet Union and the United States, meeting shortly after next month’s East German election to discuss unification.

But Poland has demanded to be included in the group and other states bordering Germany are unhappy at their exclusion from the decision-making forum.