There were some very good posts on the subject over at the Mormon Apologetics and Discussion Board (Link) a while back by posters named "SMAC" and "Confidential Informant". However, the topic is on temporary ban over there so they haven't been as active. Nevertheless, the both of them are attorneys and I'd suggest doing some searches for their posts at the site. In the meantime, I will preface my "off the top of my head" reply by saying I am not an attorney. However, while many wish to make the "slippery slope" argument go away with a wave of hand, I believe there are real dangers here. The passage of legislation allowing SSM, absent specific protections for churches to refuse the performance of such rites, is perilous. Despite the historical strong interpretation of the 1st Amendment by the U.S. Supreme Court (I realize you're in Canada), the intersection between these marriage laws and anti-hate speech legislation could easily lead to civil rights complaints and a determination that the gov't could try to force churches to perform these marriages despite their objections. While I know you've said you've never heard such things being called for by GLBT activitists, I'm afraid I have, and it concerns me. Setting aside any moral objections to the issue, the fact that the word "marriage" has both civil and religious meaning and consequences is a real problem. For this to be resolved, something will need to be done to relieve that tension. Either specifically protect churches, or take the state out of the marriage business altogether. I don't think there's a middle ground here. Incidentally, I'd suggest some additional reading on at least one area of the world where some believe SSM has had a significant impact on the heterosexual institution of marriage: Link