was not until after Sputnik in late 1957 that Eisenhower quickly moved to expand nuclear collaboration with the UK via presidential directives and the establishment of bilateral committees on nuclear matters. In early 1958, Eisenhower publicly stated that amendments to the McMahon Act were a necessary condition of a test ban, framing the policy shift in the context of US commitment to its NATO allies. In August 1957, the US assented to a two-year testing moratorium proposed by the Soviet Union, but required that it be linked to restrictions on the production of fissionable material with military uses, a condition that the Soviet Union rejected. While Eisenhower insisted on linking a test ban to a broader disarmament effort (e.g., the production cut-off), Moscow insisted on independent consideration of a test ban. On 19 September 1957, the US conducted the first contained underground test at the Nevada Test Site, codenamed Rainier. The Rainier shot complicated the push for a comprehensive test ban, as underground tests could not be as easily identified as atmospheric tests. Despite Eisenhower's interest in a deal, his administration was hamstrung by discord among US scientists, technicians, and politicians. At one point, Eisenhower complained that "statecraft was becoming a prisoner of scientists." Until 1957, Strauss's AEC (including its Los Alamos and Livermore laboratories) was the dominant voice in the administration on nuclear affairs, with Teller's concerns over detection mechanisms also influencing Eisenhower. Unlike some others within the US scientific community, Strauss fervently advocated against a test ban, arguing that the US must maintain a clear nuclear advantage via regular testing and that the negative environmental impacts of such tests were overstated. Furthermore, Strauss repeatedly emphasized the risk of the Soviet Union violating a ban, a fear Eisenhower shared. On 7 November 1957, after Sputnik and under pressure to bring on a dedicated science advisor, Eisenhower created the President's Science Advisory Committee (PSAC), which had the effect of eroding the AEC's monopoly over scientific advice. In stark contrast to the AEC, PSAC promoted a test ban and argued against Strauss's claims concerning its strategic implications and technical feasibility. In late 1957, the Soviet Union made a second offer of a three-year moratorium without inspections, but lacking any consensus within his administration, Eisenhower rejected it. In early 1958, the discord within American circles, particularly among scientists, was made clear in hearings before the Senate Subcommittee on Nuclear Disarmament, chaired by