If you were an American expatriate living in China, and you had some connections to some of US government's political rivals, what would CIA do to you when you went back to US? The term " National Security" has the highest priority in US legislation system, it can override anything else. How many dirty deals , how many illegal kidnaps and assassinations US goverment has done under this seemingly holy name! We live in a dirty world, where power is everything, where politics is the philosophy of survival. It's just that in North America the problem manifests itself in a more secret way, a more subtle way. So, just take it.