A member of the Communist Party of Great Britain, through the Connolly Association he was one of the key figures, along with Roy Johnston, responsible for inserting Marxist perspectives into the 1960s Irish republicanism, in relation to the Northern Ireland civil rights movement.
[1] During the 1950s Greaves used his influence at the Connolly Association to push the view that the best path to a United Ireland would be to discredit Ulster Unionism in the eyes of British Politicians.
However, by the end of the 1950s their efforts were bearing fruit; for example, the Association was able to raise the issue of hundreds of prisoners being detained without trial in Northern Ireland under the Special Powers Act of 1922.
Greaves and the Connolly Association would continue to push Labour against the Unionists into the 1960s, which would later prove to be a key piece of political strategy on the eve of The Troubles.
The Desmond Greaves summer school is held each year as a forum for discussing topics which exercised him, such as Irish left wing, and republican politics.