Well, yeah.
So what you do is make sure you don't try to run off half the coalition -- i.e. if homosexual marriage and abortion are positions in which you know they are unwilling to compromise don't support it and expect to keep their votes.
Similar things could be said about gun rights, tax increases, labor issues etc.
The coalition was built around political issues. If the socials now insist that their social beliefs be a part of the deal, then they're ending the coalition.
I don't believe ya'll can win a referrendum on abortion. But that's just my guess, of course.