They have to get around this first without a two thirds majority. Never happen!
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
— The First Amendment to the U.S. Constitution
It has started already without the benefit of amending the constitution. Just label it a hate-crime to get around it. I don't believe any cases have gone as far as SCOTUS yet, but since there is so much legislation from the bench, it is just a matter of time before it happens. A case in point is the Philadelphia Five who were arrested, Bibles in hand, to protest the gay-rights parade.