The police officer, he pulls you over and he sees illegal contraband in plain view. So, he has probable cause to believe that's contraband and he wants to search your car for evidence of that contraband. If he has the probable cause to go get a search warrant, the Carol doctrine says he doesn't have to have a search warrant because it's a car. And since it's movable, the courts have allowed him to search without a warrant because he doesn't have time to go get one. Now, I disagree with that. I think that case law has outlived its usefulness the day and age of telescreens. You have the ability to get a search warrant quicker than you did back in 1940. And I think the cops should be required to get a search warrant even if they have probable cause. But, the Carol doctrine gives them the right to search without a search warrant if they have probable cause.