If a U.S. citizen knowingly joins or assists a foreign terrorist organization they should have their passport and status as a citizen revoked to prevent them from harming other Americans. The current standard for revoking the citizenship of terrorists isn’t broad enough.
Revoking a person’s U.S. citizenship for “providing material assistance” to terrorists is problematic, as material assistance could be broadly interpreted and lead to violations of the person’s rights. The current standard for revoking the citizenship of terrorists works.