An interesting contention from Wilentz is that Reagan got it right in a big way on the so-called “Euromissile” controversy (the subject of the memorable “99 Luftballoons”). Wilentz says not only that the predictions of the naysayers proved wrong (which is clearly true) but that this was no sideshow. Rather, it “was a very important showdown in the history of the Cold War” and “may have played a role in Gorbachev’s emergence in 1985.” I’d be interested in learning more about the evidence here. It’s plausible enough that a failure of the Soviet hardliners in 1983 could have played an important role in Gorbachev’s rise, but then again it might not be true. You’d really need to be a Soviet specialist to understand its role fully.
Either way, as Wilentz says the key move came later, when Gorbachev did come to power and Reagan broke with the bulk of the conservative movement to decide to cooperate in good faith with the Soviet reformers. Wilentz attributes this to the fact that Gorbachev had more experience with the left going back to the 1930s and 40s and thus was more sensitive than a typical conservative to changes within the Soviet leadership.