Well, you can start with National Security Directive 75, which changed U.S. policy towards the Soviet Union from one of ‘Detente’ and ‘Coexistance’ to an active attempt to bring the regime down through political, social, and economic pressure.
I know the ‘conventional wisdom’ among many on this board is that the cold war just happened to end on Reagan’s watch, and he was just lucky to preside over an inevitable collapse, but the facts don’t bear that out. I remember 1979 well. The seeming rise of the Soviet Union and the concurrent problems with the U.S. economy had people thinking the Soviets were winning. They had huge natural resource advantages. John Kenneth Galbraith, that favorite of the left everyone, claimed, “the Russian system succeeds because, in contrast to the Western industrial economies, it makes full use of its manpower.”
The strategy of the cold war up until Reagan was one of containment and deterrence. Everyone thought the Russians would be around forever, so it was all about co-existence. Reagan changed all that. He called the Soviets an evil empire. He rebuilt the U.S. military. He threatened them with SDI. He attacked the Soviets on the periphery of their empire, greatly increasing CIA support of the Mujahadeen in Afghanistan, and funding rebels in Cambodia, Nicaragua, and elsewhere. He put pressure on client states by giving strong speeches on their lack of freedom and demanding that the Soviet Union release them. He gave his famous Berlin wall speech.
He also put pressure on them economically. There was a proposed oil pipeline to Europe from the Soviet Union, which would have given the Soviets billions in oil revenues. Reagan pressured Europe into cancelling the plans.
Again, this was all quite new. For people to claim now that the cold war was just proceeding as usual and suddenly the Soviets collapsed is a re-invention of history. Reagan changed the entire direction of the cold war, and he did it to howls of protests from his opponents, who were all about ‘understanding’ the Soviets and ‘learning to live with our differences’. On the left, hatred of Reagan was every bit as virulent as the hatred of GW Bush today. He was a goddamned crazy cowboy who was going to start World War III. His determination to put cruise missiles in Europe launched protests around the world. When he called the Soviet Union an ‘Evil Empire’, the left went bananas. When he announced SDI, it was immediately dubbed ‘Star Wars’ and it was considered to be Reagan’s folly. Except by the Soviets. Reagan used the threat of a non-existent missile defense to extract huge concessions from the Soviets. They were terrified by it.
This is not to say that Reagan was solely responsible. Pope John Paul II, Margaret Thatcher, Lech Walesa, and many, many other leaders were putting pressure on the Soviets as well. But it was Reagan who led the charge, and provide the guns and butter, and changed the direction of the cold war. He deserves huge amount of credit.
Reagan was right, his opponents were wrong, and the world is much better off that he didn’t knuckle under to their demands.