RB, one thing I ought to clarify, just so you understand where I'm coming from here, clearly there was an arms race going on and Reagan did spur our efforts. The Russians did respond and attempt to match our pace as well.
Yet, and this is the part that's crucial from where I sit, they didn't have to. No one can win a nuclear war on the scale the two nations would have fought. The earth would have become unlivable for us. It doesn't necessitate direct hits or anything like that if you can kill the planet.
So Reagan certainly practiced one-upmanship, causing the Russians to try to keep up at a time when pretty much everything else was going wrong for them. Yet they always had the option of letting us run the arms race by ourselves and it was their internal problems not directly of our making which caused their power base to erode. Without those other factors I'm fairly sure the Russians would have figured out to put their digits together and escape the fingertrap, leaving Reagan with an arms gambit that got us nowhere.
What I give Reagan far more credit for is keeping cool when Konstantin Chernenko was itching for a fight and for negotiating earnestly with Gorbachev. Fred Kaplan wrote an excellent piece in Slate yesterday on that latter point. Here's the link:
It really was a case of two leaders who bluffed their own advisors and recognized their most natural ally was the guy on the other end of the table.