The United States has a long history of unwarranted surveillance on its citizens, mostly stemming from the Patriot Act signed into law after the September 11 attacks. The Patriot Act allowed various law enforcement agencies to conduct surveillance on citizens (without warrants) in the name of protecting against future terrorist attacks, and while that law has lapsed, a new amendment passed by the U.S. Senate once again allows law enforcement to rummage through your internet history with no probable cause.