I believe if Stephane Dion whips tomorrow's SSM vote and threatens any Liberal MP with expulsion from caucus, Liberal MP John MacKay will still vote against SSM by voting for the motion.
I'm willing to put my money where my mouth is. I will take any bets up to $200 in total. All bets payable to FreeDominion. If Dion decides to keep MPs in caucus regardless of how they vote, all bets are off.