[Stavka2]

except one of these Germans was actually a U.S. citizen

Wrong. Once he joined the military of a recognized foreign power, he lost his citizenship. Padillo was never a member of an established enemy military.

[ninenot]

Once he joined the military of a recognized foreign power, he lost his citizenship

Citation, please?

THere are at least a few Americans who joined the Israeli Army and NEVER lost their American citizenship.