Capital controls in America?

I questioned some of my professors and peers back in college about the potential for capital controls, and I expressed my fear that they would happen. They all highly doubted that the government would implement any sort of capital control. Well, now the Senate has a bill to severely punish those who chose to renounce their US citizenship over taxes. This bill was introduced by one of the worst control freaks in the Senate, Chuck Schumer , and Pennsylvania Senator Bob Casey. The "Ex-Patriot Act" attempts to re-implement taxes on those who expatriate, introduce 30% capital gains taxes on them, and ban them from every coming back to the United States. This is not a patriotic bill. I think that the intent of the bill is two-fold - to continue to squeeze as much revenue into the government, and for the government to make individuals who want to leave feel threatened. Freedom to move your capital is a fundamental human right, and any attempt by the state to interfere is wrong. I hope my fear of capital controls is overblown, but the introduction of this bill furthers those fears.