"Religious institutions can confirm if a couple is married, my argument is simply to get the government out of the marriage question all together."
Will there be any governmental restrictions as to whom a religious institution can deem married? If there are, the government is still in the marriage business. If not, then suddenly any two or more humans of any status will effectively be able to get married, via such religious institutions. And even then the government will be in the marriage business, to the extent it restricts marriages to intra-species hookups. With all due respect, you really need to think this through better. There is no escape from the government being in the marriage business, because a basket of rights and duties attends the relationship.
And of course, restricting it to "religious" institutions would be unConstitutional, as favoring religion, as opposed to the government taking a neutral status, so how does one deal with that little detail?
We really need to get Rand Paul to participate in this thread. Where is he?