Remember that all Jews are dual citizens. Even if you stripped them of their Israeli passport, made it illegal to hold dual citizenship, and made them pledge loyalty to America all they need to do is make their way to an Israeli airport and they will be made citizens of Israel (subject to a DNA test of course). Thus, regardless of the legal mechanisms involved, they will always be dual citizens. It's implied to every Jew from the time they can attend Jewish classes that regardless of their country of residence, Israel is their true homeland. These are people who will never be loyal to their host country.