ACLU v. Mattis and the Citizen Enemy Combatant in Hamdi v. Rumsfeld

You lose your constitutional rights when you suit up as a foreign enemy of the United States of America. We should be killing enemy combatants not giving them rights and a taxpayer funded trial.

According to 8 U.S.C. 1481 - LOSS OF NATIONALITY BY NATIVE-BORN OR NATURALIZED CITIZEN, there are seven ways a "native-born" U.S. citizen can lose their citizenship:

1) Becoming a naturalized citizen of another country after age 18.
2) Formally declaring allegiance to a foreign government after age 18.
3) Accepting a position in the government of another country after age 18, if one has citizenship in, or declared allegiance to, that country.
4) Joining the military force of another country either (1) in any capacity if that country is engaged in hostilities against the U.S., or (2) as an officer.
5) Formally renouncing U.S. nationality abroad before a U.S. diplomatic or consular officer.
6) Formally renouncing U.S. nationality in the U.S. when the U.S. is at war, if done in writing and with the approval of the U.S. Department of Justice.
7) Being convicted of treason or participating in any attempt to overthrow the U.S. government.

So, the legal difficulty is whether the Islamic State is a "state." (We may need Bill Clinton's lawyers here) Obviously, in order to join ISIS, he had to declare allegiance to the Islamic State (#2) and maybe be recognized by them (#1). Likewise, since he was fighting for ISIS, he joined their "military force." (#4) I'm sure legal wrangling, especially if presented to a sympathetic, left-leaning court, he'll still be considered a U.S. citizen. (Even though, in reality, he switched allegiances.) In that case, U.S. attorneys need to charge and convict on #7. After that, he's no longer a "citizen."

Is shooting them on the spot too harsh?