Not if he said it on the floor of the Senate.
U.S. Constitution Art II, sec 6 : ... "for any Speech or Debate in either House; they shall not be questioned in any other place".
West Virgina is an illegitimate state anyway. The Constitution says, in Art. IV sec. 3, that (a) new state(s) shall not be formed out of existing states without the permission of the Legislature of that state. The Virgina legislature gave no such permission. It could of course be argued that Virgina wasn't a state at the time, but then the North was fighting a war of conquest, not putting down an insurrection. If was OK for W. Va. to seceed from Virgina, why not Virgina from the United States? Politicians are not known for consistancy in Constitutional interpretation.