Credits: ETIENNE LABERGE/QMI AGENCY
Candidates had until midnight on Jan. 13 to launch their campaign. They needed to gather the signatures of 300 party members and pay a $75,000 entrance fee.
During his time in Jean Chretien's cabinet, Cauchon, 50, introduced gay marriage legislation and led efforts to decriminalize marijuana.
He held the Montreal-area riding of Outremont between 1993 and 2004. That riding is now represented by NDP leader Tom Mulcair.
The other eight candidates for the leadership of the federal Grits are Justin Trudeau, former constitutional adviser Deborah Coyne, Montreal MP Marc Garneau, former Toronto MP Martha Hall Findlay, retired Canadian Forces officer Karen McCrimmon, Vancouver MP Joyce Murray, Toronto lawyer George Takach, and Ottawa lawyer David Bertschi.
The first leadership debate is scheduled to take place in Vancouver on Sunday.