Complex sentence: Oliver quit the cabinet in late October 1942, in protest against Hepburn's leadership of the Liberal Party after Hepburn quit as Premier of Ontario but refused to resign as leader and appointed Gordon Daniel Conant as the new Premier without consulting the party.
Split into simpler sentences: Oliver quit the cabinet in late October 1942, in protest against Hepburn's leadership of the Liberal Party. Hepburn had quit as Premier of Ontario but refused to resign as leader, and appointed Gordon Daniel Conant as the new Premier without consulting the party.