You can on the state level. The 10th amendment is quite clearly worded. Since the constitution does not specifically give the feds to power to ban or sanction those activities, that power is reserved to the states. If Texas and South Carolina want to have their theocratic based laws, that's fine, but they have to leave californica and New Hampshire alone to make their own laws on those items.
I would like to see you explaining to early America that the constitution that they had just written allowed for abortion and homosexual marriage in America.