On 6 May 1954 and again on 13 May, Claude Hettier de Boislambert effectively challenged the government over its Indochina policy. He stressed the interconnectedness of question involving the and Indochina. He said, "The problems we face are even more serious than the barbed wire of Điện Biên Phủ. Because it is our presence in Asia, the structure and cohesion of the entire French Union, which is challenged". He refused to express confidence in the government. "As we think with anguish about our wounded, about the ones who are fighting, about the hardships they undergo, many of us will answer 'no' when asked to express confidence [in the government]". He added, "It is the glory of our military that allows for an honorable negotiation which cannot in any way ... be seen as a capitulation". The next day the fighting stopped at Điện Biên Phủ. On 13 May Hettier de Boislambert again refused, "on behalf of his friends", to accord confidence to the government. On 25 May 1954 he was appointed by the Commission for Overseas Territories to membership of the coordinating committee for examining the country's problems associated with Indochina. Then on 12 June 1954 he again refused to give his confidence to the government, and was thereby instrumental in its collapse. Accordingly he backed the installation of Pierre Mendès France as prime minister, backing his investiture and his Indochina policy. He supported Général Aumeran in the vote of 30 August 1954 which effectively rejected, without a debate, the European Defence Community in the wake of the . On 4 February 1955 he again backed the government over its policy in North Africa (though the government nevertheless lost the vote).