Liberal Party of Australia
Menzies ran strongly against Labor's plans to nationalise the Australian banking system and, following victory in the 1949 election, secured a double dissolution election for April 1951, after the Labor-controlled Senate refused to pass his banking legislation. The Liberal-Country Coalition was returned with control of the Senate. The Government was returned again in the 1954 election; the formation of the anti-Communist Democratic Labor Party (DLP) and the consequent split in the Australian Labor Party early in 1955 helped the Liberals to another victory in December 1955. John McEwen replaced Arthur Fadden as leader of the Country Party in March 1958 and the Menzies-McEwen Coalition was returned again at elections in November 1958 – their third victory against Labor's H. V. Evatt. The Coalition was narrowly returned against Labor's Arthur Calwell in the December 1961 election, in the midst of a credit squeeze. Menzies stood for office for the last time in the November 1963 election, again defeating Calwell, with the Coalition winning back its losses in the House of Representatives. Menzies went on to resign from parliament on 26 January 1966.

Q: What helped the Liberals to victory in December 1955?
the formation of the anti-Communist Democratic Labor Party (DLP) and the consequent split in the Australian Labor Party early in 1955