I'm not allowed to hold public office in Tennessee!
Article IX, Section 2 of the state's constitution reads (h/t Incongruous):
"No person who denies the being of God, or a future state of rewards and punishments, shall hold any office in the civil department of this state."
Apparently my home state, Pennsylvania, is among six other states with a similar clause (in its case, Article 1, Section 4), although technically it just implies that it is not the case that atheists are not disqualified:
"No person who acknowledges the being of a God and a future state of rewards and punishments shall, on account of his religious sentiments, be disqualified to hold any office or place of trust or profit under this Commonwealth."
Isn't that fun? More reason why I have no intention of ever living in Tennessee or Pennsylvania again!