At about this period, Dixon was in the majority in important constitutional cases which declared unconstitutional pet projects of successive Labor and Liberal Governments, namely the "Bank Nationalisation case", and the "Communist Party Case". In the former, he considered that many of the operative provisions of the Chifley Government's "Banking Act" 1947 (which sought to nationalise Australia's banks) were beyond the constitutional powers of the Commonwealth Parliament. In the latter case he considered that the "Communist Party Dissolution Act" 1950 of the Liberal Government led by his old friend Menzies (which sought to ban the Australian Communist Party) could not be supported by any head of Commonwealth legislative power.