Probable Cause

Archie the arms dealer was just chillin’ at home one day, minding his own business, when all of a sudden a bunch of ATF agents pounded on his door and told him they were arresting him and searching his apartment for contraband. Archie’s watched a couple episodes of Law & Order over the years, so he asks to see their warrants. He knows that search and arrest warrants can’t be issues without “probable cause,” which means that law enforcement personnel had a reasonable belief that Archie had done what they suspected him of doing (in this case, illegally selling massive amounts of firearms).

The concept of probable cause is a central pillar of our criminal justice system. As we all remember from that civics class we took our freshman year of high school, the Fourth Amendment of the U.S. Constitution forbids citizens from being subject to illegal searches and seizures of property by the government. If the police want to nab us for a suspected crime, they’ve got to establish probable cause before they can search our homes, raid our businesses, or place us under arrest. And furthermore, once they have a warrant, they have to stick to the scope outlined in the warrant. So in Archie’s case, if they have a warrant to search his place for illicit guns, they can’t then turn around and also search it for evidence of movie piracy. They’ll need a separate warrant for that.