In America, you aren’t required by law to belong to the Catholic denomination.
What a ridiculous way to sidestep the point I made. I AM Catholic. Therefore, I cannot, as you state, “Have my religious marriage and leave the government out of it.” Maybe there are those who are so poorly committed to their faith that they would set it aside in order to avoid a bit of governmental intrusion. My faith means more to me than that—I obtained a marriage license form the state of Michigan, not with a smile on my face, but because for whatever reason that’s what the Church required of me in order to receive the sacrament.