I have felt this way from day one. No questions asked. I find it appalling that this is not the policy.
Nothing strikes quite so much of a symptom of how we have lost our way as this aspect of our approach to what it means to be a citizen of this country.
We used to revoke citizenship for this sort of thing. A friend’s father showed me an old passport from the 1950s and there was a warning printed inside the cover that said citizenship could be revoked if you went overseas and fought with an enemy of the USA.
I know my grandfather spoke of Americans who went to fight with the nazis. He said most of them simply died as nazis and were given no further thought.