Bar Code.
Yup, they'll try it thru "terrorism" or food supplies, or medical services. The old freedom vs security argument. This is why we have a CONSTITUTION and GWB appointing guys like Roberts and Alito to the supreme court. It also helps to rid the federal bench of liberals.
The TECHNOLOGY for a POLICE STATE is already here. Thus the unholy alliance of UN types, eco-marxists, demonrats, control freaks of one kind or another; are doing all they can to get you "bar-coded". Either GUARD your freedoms, or lose them. Evil prospers when good men do nothing...