President Reagan yesterday kicked off a campaign for Senate ratification of the Intermediate-Range Nuclear Forces Treaty he signed last week with Soviet leader Mikhail Gorbachev, saying that Senate hearings should "lay anxieties to rest, and help to build up the needed consensus."

Responding to criticism of the pact, which will eliminate medium-range and shorter-range nuclear weapons in Europe, Reagan said it would not "decouple" the relationship between the United States and its North Atlantic Treaty Organization allies.

"Let me assure you that we'll keep our American servicemen stationed in Western Europe. And let me ask, what more convincing form of coupling could there be than these hundreds of thousands of Americans and their dependents living and working among our European allies?" Reagan asked in an address to the Center for Strategic and International Studies.

He said the United States would not negotiate further reductions in nuclear weapons in Europe until after conventional-force imbalances are addressed, and he called also for "redressing" the Soviet advantage in chemical weapons.

The president also pledged continued American commitment to the NATO doctrine of "flexible response," under which nuclear weapons are maintained in Europe to deter a possible Soviet attack. "We'll retain a modern nuclear deterrent on the ground, in the air and at sea," he said.