He didn't realize it, but Reagan viewed nukes the same way. Samuel Wells, a Cold War historian at the Woodrow Wilson Center, who has examined all the relevant documents, put it this way in a phone conversation: "His staff, for all of the first term and most of the second, kept this out of the press, but Reagan was terribly, deeply opposed to nuclear weapons—he thought they were immoral."
Reagan's vision of SDI—a shield that would render nuclear weapons obsolete—was scientifically preposterous but, by all accounts, genuine. Many of his hawkish aides (most notably the still-active Richard Perle) scoffed at it; they liked SDI because it would scare the Russians and, if it worked, might give us nuclear superiority. But Reagan believed what he said.
At their face-to-face summit of October 1986 in Reykjavik, Reagan went far beyond Gorbachev's proposal of a 50 percent strategic-arms cut. To the alarm of some aides, who were not let in on the discussion, he suggested that the two sides get rid of nuclear weapons altogether and jointly build an SDI system to guard against a nuclear revival. Gorbachev initially dismissed the idea. "I do not take your idea of sharing SDI seriously," the minutes (which were declassified by the Soviets 12 years ago) show him saying. "You don't want to share even petroleum equipment, automatic machine tools, or equipment for dairies, while sharing SDI would be a second American revolution—and revolutions do not occur all that often." Reagan replied, "If I thought that SDI could not be shared, I would have rejected it myself."
The Reykjavik talks finally fizzled. Gorbachev said he'd accept the zero-nukes plan if Reagan pledged not to test nuclear weapons in outer space (a crucial element of SDI). Reagan wouldn't accept that condition.
However, Gorbachev returned to Moscow persuaded that Reagan—who had earlier struck him as a "caveman"—honestly had no intention of launching a first strike against the Soviet Union, and he made this point clear to the Politburo. He could continue with perestroika, which involved not just economic reforms but—as a necessary precondition—massive defense cuts and a transformation of international relations. He needed assurances of external security in order to move forward with this domestic upheaval. Reagan gave him those reassurances. Subsequent conversations between his foreign minister, Edvard Shevardnadze, and Secretary of State George Shultz reinforced his confidence.
In the last couple years of the Reagan administration, Reagan would propose extravagant measures in arms reductions. His hawkish aides would go along with them, thinking the Soviets would reject them (and the United States would win a propaganda victory). Then, to the surprise of everyone (except perhaps Reagan, who meant the proposals without cynicism), Gorbachev would accept them.
In the end, Reagan and Gorbachev needed each other. Gorbachev needed to move swiftly if his reforms were to take hold. Reagan exerted the pressure that forced him to move swiftly and offered the rewards that made his foes and skeptics in the Politburo think the cutbacks might be worth it.
Gorbachev wasn't the only decisive presence. If Reagan hadn't been president—if Jimmy Carter or Walter Mondale had defeated him or if Reagan had died and George H.W. Bush taken his place—Gorbachev almost certainly would not have received the push or reinforcement that he needed. Those other politicians would have been too traditional, too cautious, to push such radical proposals (zero nukes and SDI) or to take Gorbachev's radicalism at face value. (There's no need to speculate on this point. When Bush Sr. succeeded Reagan in 1989, U.S.-Soviet relations took a huge step backward; it took nearly a year for Bush and his advisers to realize that Gorby was for real.)
The end of the Cold War may be the most oddball chapter in the history of the 20th century. How fitting, then, that the two most oddball leaders, Gorbachev and Reagan, made it come to pass.