I have noticed several petitions requesting that anyone who has signed a petition to have their state peacefully withdraw from the United Sates of America and create its own new government have their citizenship stripped and be deported from the country.
The 1st amendment to the U.S. constitution prohibits the making of any law abridging the freedom of speech, infringing on the freedom of the press, interfering with the right to peacefully assemble or prohibiting the petitioning for a governmental redress of grievances (the right to make a complaint or to seek the assistance of ones government without the fear of punishments or reprisals.)
Due to the 1st amendment, I believe that stripping any Americans citizenship for practicing their right to freedom of speech to be unconstitutional.