As American lawmakers face the pressures of the November election, President Reagan is winning the battle with Congress to provide United States military aid to the guerrillas fighting the Nicaraguan government. Assuming the House bill is reconciled with a similar Senate bill approving $100 million in military and economic assistance for the so-called ``contras,'' diplomatic observers see such action as having two major results:
It will give the President a freer hand in his Central America policy, opening the way to successive increments of aid for the anticommunist insurgency and to increased US involvement in the Nicaraguan conflict.
It will deal a blow to the Contadora peace process aimed at a negotiated regional settlement of the conflict. The Central American countries, seeing that both the President and Congress are behind support for the contras, may become more assertive in backing the policy.
Some diplomatic experts suggest that the House action this week may also sharpen debate over the whole issue of US policy in Central and Latin America.
``There may be a rethinking of fundamental issues,'' says Peter Hakim, staff director of the Inter-American Dialogue, a group supporting a negotiated settlement in Central America. ``The issue of whether the US should be supporting the military overthrow of an established government has been lost in the effort in Congress to find some middle ground.''
Mr. Hakim says the House lawmakers never came to grips with what is meant by negotiations, with how to make the Contadora process more effective, or with the question of US interventionism. The latter issue will be highlighted today when the World Court in The Hague is expected to rule that US support for the contras violates international law.
Some foreign policy experts, however, say that no national debate is likely to be generated unless the President threatens to send in the US Marines or until some leading political figure challenges present administration policy. With an election looming, lawmakers do not want to appear tolerant of the Marxist Sandinista regime -- or to be seen opposing a popular President -- even though polls show that the vast majority of Americans remain opposed to US military and other aid to the Nicaraguan rebels.
``The House vote shows that the Congress is incapable of having any policy six months before an election,'' says Charles William Maynes, editor of Foreign Policy magazine. ``If you could get a secret vote, Reagan would lose . . . but no one wants to take a chance.''
Most diplomatic observers agree that US support for the contras could become costly. Few believe that $100 million, including $70 million in military aid, is enough to bring the Sandinistas to heel. Even $500 million is seen as insufficient, given the military strength and political determination of the Sandinista regime.
But supporters of administration policy say that $100 million will go a long way in helping forge a guerrilla army, which above all needs training and small arms.
``The House action sends a big signal to the Nicaraguans, who have to be afraid the contras will not fold up,'' says Robert Leiken, a Central America expert at the Carnegie Endowment for International Peace. ``It will also be a big morale booster for the troops [guerrillas].''
Whether the contras can alter the situation in Nicaragua is a matter of dispute. Dr. Leiken suggests that, if diplomatic and military pressures increase to the point where the Sandinistas feel they can no longer govern and cannot defeat the guerrilla movement, new elections become a possibility.
But, he stresses, this depends on a concerted effort by all rebel groups and on civilian control of the contras -- which the President is now stressing.
Other specialists say nothing short of an American military intervention will defeat the Sandinistas, who will simply call for increased Soviet-bloc aid in the face of a growing guerrilla movement.
There remains considerable confusion about the President's bottom-line goal in Nicaragua. Administration officials say the aim of helping the contras is to foster a democratic government in Nicaragua, i.e., to pressure the Sandinistas to the point where they either compromise with the opposition and hold elections or are overthrown.
``Our goal is a democratic outcome,'' says a State Department official. ``They can choose which way to go -- whether to fight it out and be overthrown or compromise . . . This is a national security issue. You have a country that is manifestly involved in subverting its neighbors, and there is only one country capable of dealing with Nicaragua.''
The question is how far the President is prepared to go to sustain the contras and bring about political change. Administration officials say there is an ``indefinite commitment'' to help the insurgents. But Reagan has been careful to say that he does not intend to commit US forces to the region.
The administration appears divided on the question. Some forces in the administration would go so far as American intervention if necessary to overthrow what they deem an intolerable Marxist beachhead in the Western Hemisphere. Others are content with a policy that simply keeps up pressure on Nicaragua and enables the President to show that he is against acceptance of the communist Sandinista regime.