Frontrunners include Chrystia Freeland and Mark Carney, who are making the case they can guide Canada through domestic and international issues. At the top of the list: mounting trade tensions with the United States.

Why it matters: Liberal Party members' vote for Mark Carney, former governor of the Banks of Canada and England, comes as the Liberals are experiencing a polling boost amid widespread opposition to President Trump's U.S. policies targeting its northern neighbor.

Carney, a political novice, will take over at a tumultuous time in Canada, which is in the midst of a trade war with longtime ally the United States and must hold a general election soon.