Original sentence: Liberal Party leader John Turner was put into a tough position, considering the popularity of the agreement in Quebec (a traditional Liberal stronghold) and the Trudeau ideal of federal power
Edited sentence: Liberal Party leader John Turner was put into a tough position, considering the popularity of the agreement in Quebec (a traditional Liberal stronghold until Trudeau’s repatriation of the Constitution in 1982; ever since, Québec has stopped to overwhelmingly vote liberal) and the Trudeau ideal of federal power