In a major statement of America's foreign policy to allies, neutral countries , and, above all, the Soviet Union, Secretary of State Alexander Haig has prepared the way for arms control initiatives that President Reagan will take later this year.
A likely change of leadership in the Soviet Union is producing ''a historic opportunity'' for a reappraisal of US-Soviet relations, Mr. Haig said. He set out to redefine the situation in a speech here to the US Chamber of Commerce. An aide called it ''an important foreign policy address.'' President Reagan is also scheduled to make a set of major foreign policy declarations soon aimed at opening new strategic arms negotiations.
Secretary Haig wants to let the Soviets know, it appears, that the United States is resolute but reasonable. He is addressing three audiences besides Moscow in his carefully prepared statement. He is telling European allies they can count on the United States; he is telling disaffected third-world countries that there is a better way than Marxism, an ideology which, he said, ''has little to offer but the tools and techniques of violence''; and he is telling American antinuclear activists that the government intends to be firm but open-minded on nuclear defense, while warning right-wing hawks not to damage relations with European allies.
Mr. Reagan is expected to follow these same themes when he visits Europe early in June and addresses a UN General Assembly session on disarmament in New York later that month.
''Today it has become essential for the United States and its allies to deal with the realities,'' Haig began. In broad strokes, he said that global military balance has been changed by ''lagging Western strength''; interdependence has grown within the West and, simultaneously, the Soviet Union has been ''increasingly bold in the use of its might to promote violence.'' Can we change these latter trends? Yes, says Haig, ''I believe that we can.''
In a three-part analysis, Haig began with the need to strengthen ties to allies. It is ''essential,'' he said in the course of his comments, ''to go forward with the modernization of intermediate-range nuclear systems while simultaneously pursuing arms-control negotiations.''
His second theme was the third world. The message was simple: The Marxist-Leninist ''locomotive,'' Haig said, ''has not become an engine for progress.'' He urged third-world leaders, in effect, to change trains.
The third and most important Haig commentary was on the Soviet Union. Washington widely believes the rule of President Brezhnev is nearing its end. Haig traced the rivalry of the superpowers. He warned Americans against ''extremes'' in meeting the challenge, either reckless good will or threats of confrontation. His conclusion:
''An American approach to the Soviet Union that balances strength and negotiations offers the best hope of significant accomplishment.'' He declared that the Soviets' ''attempt to change the balance of power'' has produced a ''backlash'' of resentment. Now, he said, the time may be ripe for change:
'' . . . As a new generation of Soviet leaders emerges,'' he said, ''we can signal the benefits of greater restraint.''