Quote Originally Posted by davidbfpo View Post
Has he committed a criminal offence by fighting for a foreign cause then?
In the US there are in place federal laws forbidden the participation in a "mercenary unit or being a mercenary"....was put into place during the "wars of liberation in Africa and South America" during the period when a lot of Americans were cruising in Africa dealing in weapons and fighting as mercenaries for hire.

Currently Ukraine as issued an Interpol and Europol arrest warrant for war crimes against him that in turn should place him then on the no fly list into the US...in theory...then CBP should detain him....

BUT unless he is flying United I do not see him being forced off any United flight....