What I think is the Constitution does say “We the people” have a right to form a contract.
I also believe Marriage is between one man and one woman and is a Sacrament before God.
They don’t need “special marriage” to use legal wills and power of attorney. Homosexuals already have the legal means to do as they will. They always have had. What they want is their aberrant behavior normalized and special rights. Giving special rights based on behavior is nowhere in the Constitution.