Reagan agreed to meet at the 1985 Geneva Summit, where they issued a joint statement indicating that neither the U.S. nor the Soviet Union would "seek to achieve military superiority." The two leaders began a private correspondence after the summit, and each became increasingly optimistic about arms control negotiations. Reagan's willingness to negotiate with the Soviets was opposed by many conservatives, including Weinberger; conservative columnist George Will wrote that Reagan was "elevating wishful thinking to the status of a political philosophy." Various issues, including intelligence operations performed by both countries and tensions in Germany and Afghanistan, threatened to forestall the possibility of an agreement between the United States and the Soviet Union. Nonetheless, both Gorbachev and Reagan agreed to continue arms control negotiations at the October 1986 Reykjavík Summit. At the summit, Gorbachev and Reagan closed in on an agreement to greatly reduce or eliminate the nuclear stockpiles of both the U.S. and the Soviet Union over a ten-year period, but the deal collapsed due to disagreements regarding SDI development. Reagan attacked Gorbachev in a 1987 speech delivered in West Berlin, but negotiations continued. Gorbachev and Reagan broke the impasse by agreeing to negotiate separate treaties on intermediate nuclear forces (such as intermediate-range ballistic missiles) and strategic arms (such as intercontinental ballistic missiles). With the framework for an agreement in place, Reagan and Gorbachev met at the 1987 Washington Summit. They signed the Intermediate-Range Nuclear Forces Treaty (INF Treaty), which committed both signatories to the total abolition of their respective short-range and medium-range missile stockpiles. The agreement marked the first time that the United States and the Soviet Union had committed to the elimination of a type of nuclear weapon, though it provided for the dismantlement of only about one-twentieth of the worldwide nuclear weapon arsenal. The treaty also established an inspections regime designed to ensure that both parties honored the agreement. In addition to the INF Treaty, Reagan and Gorbachev discussed a potential strategic arms treaty, known as START, but SDI continued to be a major point of contention. In May 1988, the Senate voted 93-to-5 in favor of ratifying the INF Treaty. Though it was attacked by conservatives like Jesse Helms, the INF Treaty provided a major boost to Reagan's popularity in the aftermath of the Iran–Contra Affair. A new era of trade and openness between the two powers commenced, and the U.S. and the Soviet Union cooperated