I wonder what effect the referendums in WA and MD would have on current law if majorities vote against gay marriage.
Its going before the Supreme Court soon, if gay marriage wins a referendum, the gay lobby will use it as proof of changing public opinion. If Supreme Court buys the narrative that society chose this path, they may chose to expedite the process. Which is why it is so important that these measures fail (and the one in Minnesota passes).
That said, DOMA is probably unconstitutional atleast in part. It allows one state to not recognize another states marriage license, which likely violates full faith and credit clause of US Constitution. If Texas allows 16 year olds to marry, and New Mexico does not, a couple married in Texas does not become divorced if they move to New Mexico. It will be very hard to justify and explain why same sex marriage is an exception.