Everyone here thinks social conservatism would ruin the party's chance to win. I disagree. For certain, abortion and ssm are #1 on the media's agenda, but I don't think average Canadians care all that much about those things.  Canadians have never voted in a referendum on those things, and 99.9% of Canadians do not belong to any organization that advocates for those things one way or the other. 
In fact, Paul Martin, the PM who passed ssm in 2005 lost the next election shortly after- and the politician that promised a re-do on that vote, S. Harper, won the next election. 
Here in Ontario, no politician has ever done more for "progressive" values than premier Wynn, and she has the lowest poll rating in recent memory. 
Canadians vote with their wallets. They also like their social programs. Threats to pensions, medicare, school systems etc, are much more alarming.