Well first, treason specifically is very narrowly defined in the US. >Treason against the United States, shall consist only in levying War against them, or in

Well first, treason specifically is very narrowly defined in the US. >Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort. They didn't levy war against the US, or adhere to an enemy (because the UAE isn't one). But in general, it's not illegal for US citizens to join foreign armies (if they aren't enemies). Lots of Jewish citizens, for example, serve in the IDF. "According to the U.S. code, any citizen who "enlists or enters himself, or hires or retains another to enlist or enter himself, or to go beyond the jurisdiction of the United States with intent to be enlisted or entered in the service of any foreign prince, state, colony, district, or people as a soldier or as a marine or seaman … shall be fined under this title or imprisoned not more than three years, or both." But a court ruling from 1896 involving U.S. citizens who fought with Cuban revolutionaries against Spanish colonial rule interpreted this to mean that it was only illegal for citizens to be recruited for a foreign army in the United States, not to simply fight in one." https://foreignpolicy.com/2011/09/02/is-it-legal-for-americans-to-fight-in-another-countrys-army/ https://foreignpolicy.com/2011/09/02/is-it-legal-for-america...