He lied when he took the oath. Revoke his citizenship, then proceed.
See my previous post - the point is, in order to “revoke his citizenship,” the govt needs to go to court and prove that he lied when he took the oath. Here, that would mean the govt would have to prove that he’s associated with some jihadi group (or, if he’s a “lone wolf” that he himself is an enemy of the U.S.). The evidence for that is basically the same as the evidence in this case, so the govt would basically need to try him twice - once in court to strip his citizenship, and then before a military tribunal.
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Agreed.