The gun rights crowd considers mandatory registration as an unconstitutional overreach of federal authority and the close attention paid to all discussions on the topic show how carefully Baucus and others must tread.
The federal government is claiming with the ACA the unlimited power to control every economic decision every individual makes, which not only is a fantastic overreach of its constitutional authority but also a claim to possess the power to destroy the very Constitution from which it supposedly derives the authority to exercise the power.