[5] Many ALP members during the Cold War period, most but not all of them Catholics, became alarmed at what they saw as the growing power of the Communist Party of Australia within the country's trade unions.

These members formed units within the unions, called Industrial Groups, to combat this alleged infiltration.

A. Santamaria,[7] a Roman Catholic Italian-Australian Melbourne lawyer and lay anti-Communist activist, who acquired the patronage of Dr Mannix.

[15] On the night of 19 April 1955, Liberal and Country Party leader Henry Bolte moved a motion of no-confidence against John Cain's Labor government in the Victorian Legislative Assembly.

[citation needed] Scully had been a Minister in the Cain Government and a member of the Movement, and was expelled from the ministry and the ALP as part of the 1955 split.

The party attracted many voters among migrants from Catholic countries in southern Europe, and among anti-Communist Eastern European refugees.

[24] Journalist Don Whitington argued in 1964 that the DLP, as a basically sectarian party, was a most dangerous and distasteful force in Australian politics.

[26][27] At least one source claims it was renamed in 1956,[28] but this appears to have been the founding of a DLP in New South Wales (where an ALP split had largely been avoided).

The DLP Senate leaders were George Cole (from Tasmania; 1955–1965),[44] Vince Gair (from Queensland; 1965–1973),[45] and Frank McManus (from Victoria; 1973–1974).

Owing largely to demographic reasons, the ALP did not split in these states, although some lay branch members switched to the new party once it had been established.

As the ALP and the conservative parties traditionally held approximately equal numbers of seats in the Senate, the DLP was able to use the balance of power in the Senate to extract concessions from Liberal governments, particularly larger government grants to Catholic schools, greater spending on defence, and non-recognition of the People's Republic of China.

However, Calwell refused to share power within the party with the DLP leadership on a membership number basis, so the deal failed.

At the 1969 federal election, DLP preferences kept Calwell's successor Gough Whitlam from toppling the Coalition, despite winning an 18-seat swing and a majority of the two-party vote.

[citation needed] From the early 1960s onward the DLP became increasingly socially conservative, opposing homosexuality, abortion, pornography and drug use.

[52] By this point, the party's emphasis on Senate results had led to a steady decline in their primary vote for the House of Representatives, and according to Tom King of Australian National University a large amount of the support for the DLP by this point came as a result of protest votes against the two major parties, rather than any definitive ideological base.

[53] A softening of attitudes towards Communism both in Australia and within the Catholic Church meant that the party increasingly sounded old-fashioned and ideologically adrift, a perception that was not helped by the advanced age of the DLP's parliamentarians.

[53] In 1974, Whitlam appointed Gair as ambassador to the Republic of Ireland in a successful bid to split the DLP and remove its influence.

In April 1978 it was reported in The Bulletin that the New South Wales state council would meet in June 1978 to determine the future of the party.