There are at least two issues... maybe more, depending on how you make lists.

1)Should the 'government' have ANY say in the rights of ANY couple to have a legal marriage with all civil advantages.

2)What should the various churches do IF the government allows any combination of couples to marry?

It seems to me, as in my earlier post, that the government should NOT take a position. Thus, couples could legally marry, whether or not their chosen church agrees to 'sanctify' the union.

Of course, many would not 'feel' married properly unless they had religious approval, but that is gradually changing as the idea that only M/F unions are 'natural'. Science is proving more every year that sexual choice is largely determined by genes and DNA and hormones, etc.
   I consider myself fortunate that I do not have to fight the system and its religious background, but in my LONG experience now, I have known enough good people who did... and who simply and honestly could NOT live a heterosexual life.

I am sad & sorry that so many still feel they must apply a religious test to all of these important matters.