Canada traditionally holds “premiership” debates between the leaders of four parties, prior to national parliamentary elections. One could consider these the Canadian equivalent of U.S. presidential debates. By tradition, any party that runs candidates for Parliament in a substantial number of Canadian districts, and which has at least one member of Parliament, is included in these debates. Recently, this has meant that the leaders of the Liberal, Conservative, Bloc Quebecois and New Democratic Parties debate.
The Canadian Green Party is pressing to be included in future debates. The Greens ran candidates in all Canadian districts in the last election, but have not yet elected anyone to Parliament. A poll announced on January 22 says that 77% of Canadians want the Greens included, 9% are opposed, and 14% have no opinion. The survey included 1,500 Canadians and was paid for by the Green Party. Note: this item has been amended to take account of information provided by a commenter.