[2] Later on 19 October 1888 Rosa moved to Sydney from America and became secretary of the Australian Socialist League.

In January 1892 he was deposed and the league began to move towards state-oriented socialism, which Rosa opposed.

He successfully sued Truth for libel in September, but in 1893 was imprisoned for three months after selling Arthur Desmond's Hard Cash.

[1] Despite the earlier disputes between him and Truth, he was appointed its editor by his friend John Norton in 1901 and worked for the paper in 1923.

He was chairman of the Industrial Vigilance Council during World War I and was expelled from the Labor Party in July 1919 together with Jock Garden and Albert Willis after they denounced the state executive as corrupt and useless.