and France in accord with the US (though France conducted its first nuclear test in February) and the Soviet Union having largely accepted the Macmillan-Eisenhower proposal. But US-Soviet relations soured after an American U-2 spy plane was shot down in Soviet airspace in May 1960. The Paris summit was abruptly cancelled and the Soviet Union withdrew from the seismic research group, which subsequently dissolved. Meetings of the Geneva Conference continued until December, but little progress was made as Western-Soviet relations continued to grow more antagonistic through the summer, punctuated by the Congo Crisis in July and angry exchanges at the UN in September. Macmillan would later claim to President John F. Kennedy that the failure to achieve a test ban in 1960 "was all the fault of the American 'big hole' obsession and the consequent insistence on a wantonly large number of on-site inspections." Eisenhower would leave office with an agreement out of reach, as Eisenhower's technical advisors, upon whom he relied heavily, became mired in the complex technical questions of a test ban, driven in part by a strong interest among American experts to lower the error rate of seismic test detection technology. Some, including Kistiakowsky, would eventually raise concerns about the ability of inspections and monitors to successfully detect tests. The primary product of negotiations under Eisenhower was the testing moratorium without any enforcement mechanism. Ultimately, the goal of a comprehensive test ban would be abandoned in favor of a partial ban due to questions over seismic detection of underground tests. Political scientist Robert Gilpin later argued that Eisenhower faced three camps in the push for a test ban. The first was the "control" camp, led by figures like Linus Pauling and astronomer Harlow Shapley, which believed that both testing and possession of nuclear weapons was dangerous. Second, there was the "finite containment" camp, populated by scientists like Hans Bethe, which was concerned by perceived Soviet aggression but still believed that a test ban would be workable with adequate verification measures. Third, the "infinite containment" camp, of which Strauss, Teller, and members of the defense establishment were members, believed that any test ban would grant the Soviet Union the ability to conduct secret tests and move ahead in the arms race. The degree of Eisenhower's interest in a test ban is a matter of some historical dispute. Stephen E. Ambrose writes that by early 1960, a test ban