[piasa]

He did not renounce his citizenship- if he did there would be a file with the documents and signd oath of renouncement in some US embassy or consulate office in Pakistan or Yemen.

As for violating the fine print on citizenship on a US passport, there are reasons not to take his citizenship based on that that would set up an awkward precedent, I think, in the way we would have to treat other members of al-Qeada.

[geaux]

He did not renounce his citizenship

Simply taking up arms against the U.S. is a renunciation of U.S. citizenship. He did not need to execute a formal renunciation.