Besides, at least one of his kids moved to the states. I suspect this had something to do with his becoming a citizen.
But your are correct - our immigration policy today is totally insane.
That's absolutely correct. Isoroku Yamamoto, who planned and let the Pearl Harbor attack, studied 3 years at Harvard and knew America well. He begged the Japanese High Command to leave us alone. He was overruled and ordered to attack, which he reluctantly did. He was not proud of attacking a "sleeping giant".