The Fourth Amendment protects us from random invasions of our homes by police, right? We know we're secure in our "persons, houses, papers, and effects" unless the cops demonstrate probable cause to a judge and get a warrant. Except... Except when they don't. The fact of the matter is that police have a lot of leeway to bust your door down and take a look around if they fear that waiting for a warrant could lead to loss of evidence or danger to people. Or lead to something, anyway. That end run around the Fourth Amendment is called "exigent circumstances,"...
