Re: "I didn't see one bumper sticker with Osama in a noose. "
Showing one constitutes a most serious felony and will get you arrested, at which point it's up to the Secret Service and FBI to assess whether to press charges and prosecute.
Even if they eventually let you go free, the incident will remain on the record and will follow you everywhere you go for the rest of your life.
Any and every time a politician is in your area, you will be placed under 24 hr. surveillance and watched very closely.
Good luck ever boarding an airliner again.
Such a thing "crosses the line" from a citizens' rights to legitimate dissent and protest, into the area of "Threatening a Federal Official", and trust me when I tell you that the trouble you will get in for owning, or displaying such "art" is very, very serious.