He became increasingly at odds with William Walker, the leading member of the Belfast Labour Representation Committee as, unlike Walker, Campbell supported Irish independence and preferred to work with the Dublin-based labour movement, rather than the London-based one.
[1] In the same year, he was elected to the Parliamentary Committee of the Irish Trades Union Congress (ITUC), and in 1911, he served as its president.
[1] In 1912, Campbell attended the Socialist Unity conference, organised by Connolly, and supported the merger of much of the Northern Ireland-based ILP with the Socialist Party, to form a new "Independent Labour Party of Ireland", although this only lasted two years before dissolving.
Campbell, Johnson and Danny McDevitt convinced the Belfast Trades Council to back the ITUC's new political levy, which established the Irish Labour Party (IrLP), and it was under this label that Campbell gave anti-war speeches and opposed the expulsion of Catholic workers from the shipyards.
However, he was very disappointed that the party stood aside at the 1918 general election, giving implicit backing to Sinn Féin.