faced mounting pressure from the Department of Defense and nuclear laboratories to set aside the dream of a test ban. In June 1961, following stalled talks in Geneva, Kennedy had argued that Soviet negotiating behavior raised "a serious question about how long we can safely continue on a voluntary basis a refusal to undertake tests in this country without any assurance that the Russians are not testing." Whether or not the Soviet Union had actually conducted secret tests was a matter of debate within the Kennedy administration. A team led by physicist Wolfgang K. H. Panofsky reported that while the Soviet Union could have secretly tested weapons, there was no evidence indicating that it actually had. Panofsky's findings were dismissed by the Joint Chiefs of Staff as "assertive, ambiguous, semiliterate and generally unimpressive." Two weeks after the lifting of the Soviet moratorium in August 1961, and after another failed Anglo-American attempt to have the Soviet Union agree to an atmospheric-test ban, the US restarted testing on 15 September 1961. Kennedy specifically limited such testing to underground and laboratory tests, but under mounting pressure as Soviet tests continued — during the time period of the Soviet Tsar Bomba 50 Mt+ test detonation on 30 October over Novaya Zemlya — Kennedy announced and dedicated funds to a renewed atmospheric testing program in November 1961. A report on the 1961 Soviet tests, published by a group of American scientists led by Hans Bethe, determined "that [Soviet] laboratories had probably been working full speed during the whole moratorium on the assumption that tests would at some time be resumed," with preparations likely having begun prior to the resumption of talks in Geneva in March 1961. In January 1962, Bethe, who had once supported a test ban, publicly argued that a ban was "no longer a desirable goal" and the US should test weapons developed by its laboratories. In contrast to Soviet laboratories, US laboratories had been relatively inactive on nuclear weapons issues during the moratorium. In December 1961, Macmillan met with Kennedy in Bermuda, appealing for a final and permanent halt to tests. Kennedy, conversely, used the meeting to request permission to test on Christmas Island, with US testing grounds in the Pacific having largely been exhausted. Macmillan agreed to seek to give US permission "if the situation did not change." Christmas Island was ultimately opened to US use by February 1962. On this