Attitudes towards Anglo-Soviet collaboration changed dramatically between May and August 1939. For the first time, nearly all members of the Cabinet, the Foreign Policy Committee and the Chiefs of Staff supported an Anglo-French-Soviet alliance. Chamberlain was alone in his opposition to such an agreement. Yet the negotiations failed and the Soviet Union signed a non-aggression pact with Nazi Germany. Neville Chamberlain must bear most responsibility for Britain's failure to secure a Soviet ally because he undermined the greatest opportunity for a successful conclusion of negotiations in May. Ultimately, however, negotiations failed because, with the exception of the Chiefs of Staff and Oliver Stanley, all members of the Cabinet and Foreign Policy Committee, chose during the final weeks to allow their ideological suspicion of the Soviet Union to once more dominate the foreign-policy decision-making process.
On 6 May, the British replied to the Soviet proposal of 18 April. Moscow received the British counter-proposal on 8 May. Again, it stated that the Soviet government should declare its willingness to aid those countries in eastern Europe who wanted help in the event of war. This time, however, it was proposed that Moscow would not have to make such a declaration until after Britain and France had gone to war with Germany. On 15 May, Moscow rejected the British proposal and again demanded a triple alliance on the reasoning that British proposals left the Soviet Union exposed to a direct attack by Germany via the Baltic states without any guarantee. 1 Still another attempt was made to secure an independent declaration of assistance from the Soviet government. On 17 May, Robert Vansittart repeated the British proposal to Maisky, adding the incentive of staff conversations. 2 On 19 May, Maisky reported that the new Soviet Commissar for Foreign Affairs, Vyacheslav Molotov, would accept nothing less than a triple alliance. 3 A breakdown of the negotiations now had to be faced. 4 Finally, on 24 May, Chamberlain agreed to an Anglo-French-Soviet alliance, although it was to be in accordance with