The Australian Labor Party split of 1955 was a split within the Australian Labor Party along sectarian and ideological lines in the mid-1950s. With the exception of the consequences of The Petrov Affair, the Liberal/Country Coalition had little or no influence on the split; it was essentially an internal conflict between elements of the Australian Labor Party.Key players in the split were the federal opposition leader H. V. "Doc" Evatt and B. A. Santamaria, the dominant force behind the "Catholic Social Studies Movement" or "the Movement".