Press: I can post all kinds of lies that I would be CIVILLY liable for but could well result in your death. Shouldn't I pass a background check before I post in the internet or put up placcards. Definately before I purchase space on a billboard.
Religion: What if my religion is that all green-eyed individuals with freckles must die. Currently until I actually kill one of them I am completely free to practice my religion. However, shouldn't I pass a background check first to see if I am too unstable to have a religion?
Assembly: If we weren't free to assemble all those people wouldn't have been standing around waiting to be blown to bits in Boston, and maybe those 2 brothers wouldn't have been allowed to attend. Lets require a background check before more than 3 people can meet. It woudl end all gang crimes a the gang members definately couln't pass a background check.
Background checks before voting or serving on a jury could be a good thing.
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Those who would sacrifice freedom for security deserve neither,
-Benjamin Franklin