 During that time, he played a role in amending Bill 101, the Charter of the French language, in opposition to the goals of Quebec separatists.In 1985 he began a private law practice, and was named the reviser of the statutes of Manitoba following the Supreme Court of Canada ruling in the Reference re Manitoba Language Rights case.Mulcair also taught law courses to non-law students at Concordia University (1984), at the Saint Lawrence Campus of Champlain Regional College in Sainte-Foy, and at the Université du Québec à Trois-Rivières.