Paul Martin Jr. (born August 28, 1938) is a Canadian politician. He was the 21st Prime Minister of Canada. He was also the leader of the Liberal Party of Canada. He became prime minister December 12, 2003, when Jean Chrétien stepped down. He won an election on June 28, 2004, because the Liberals won more seats than the other political parties; but they did not win a majority of the seats, so he led a minority government. There was another election on January 23, 2006; his party lost this election, so Stephen Harper became the next prime minister.