Prime Minister Mark Carney brought new Liberal MP Michael Ma onto the stage during the Liberals' holiday party. The Ontario MP announced Thursday that he is leaving the Conservative caucus and joining the Liberals. Ma said in a statement that he made the decision after listening to his constituents in the riding of Markham-Unionville in the Greater Toronto Area. The surprise defection moves the Liberals one seat closer to a majority government. »»» Subscribe to CBC News to watch more videos: