There’s a bill, the Enemy Expatriation Act, that aims to strip US citizens of their citizenship if they are accused of “engaging in, or purposefully and materially supporting, hostilities against the United States.” (The term “hostilities” is defined to mean any conflict subject to the laws of war.)

This is almost certainly unconstitutional. The US Supreme Court held some years ago that it was impossible for a US citizen to unintentionally give up his citizenship. In particular, formally renouncing your citizenship in front of a foreign official was not enough to actually lose your citizenship, because maybe you intended to retain your citizenship (and were just going through the motions of renouncing it as part of obtaining citizenship of some other country).

Now, the Supreme Court has become pretty unreliable on this sort of thing of late, but it seems to me that if formally renouncing your citizenship is ineffective, just in case you didn’t really mean it, then a whole lot of things that fall under the general heading of “supporting” (such as donating money to a charity that is later found to have been diverting some of that money to groups that are in some way connected with other groups that are accused of) hostility certainly don’t qualify as intentional renunciation.