Why, in any case, have we ever started such a tradition? Only because Christianity was the default setting for Americans. It is not so any longer. We live in a religiously multi cultural society.
Couples should have a civil marriage which would be open to anyone and any mixture as decided by the secular state. Then if they wish to have a religious ceremony they may do so.
This should not be a difficult change in law to enact, and it could be done easily and quickly.
This solution allows full rights to all people while protecting religious freedoms and consciences for all.
This solution is non judgmental, open, creative and positive. It gives freedom of choice while assuring freedom of religion.
Furthermore, it is a solution already in place in many European countries. In France, Italy and Germany this has been the practice for a long time.
I just wonder why no one else is proposing such a solution and am thinking that we need to start a little campaign to make this happen.