14. The United States attempted to assess the damage done by the Cambridge 5
The defection of Maclean and Burgess to the Soviet Union disrupted American plans to expose the spies in the British delegation in Washington. British intelligence’s failure to present evidence against Philby, and their subsequent exoneration of him, disrupted them further. An atmosphere of distrust and suspicion fell over the intelligence agencies of both nations during a critical period of the Cold War. The distrust became palpable, much to the delight of the Soviets. The Americans found it difficult to assess how much damage had occurred. Areas of concern included lost classified data, information about atomic and thermonuclear weapons, troops deployments, and much more. Agents formerly working for the Americans vanished.
Following the defection of Maclean and Burgess, the Americans remained convinced another mole existed in British intelligence, as well as in their own. There were several Soviet agents outside of the Cambridge 5 remaining in both the United States and Great Britain, as well as in Europe. Classified information continued to be compromised as the United States deployed tactical weapons in Europe as part of NATO. Cooperation between the intelligence agencies of the allies waned at a time when it was sorely needed. According to Yuri Modin, who handled the Cambridge 5, the lack of cooperation alone reflected a Soviet victory. In the 1950s, exchange of information between Britain and the United States regarding nuclear weapons was suspended entirely, remaining so for several years.