The “castle doctrine” has long since been abolished, the NSA spies on whomever it wants wherever and whenever (especially thanks to the PATRIOT Act), and decades of poor Supreme Court decisions have slowly eroded on the constitutional right against unreasonable searches and seizures. Today, Reason alerts us to the decision in Heien v. North Carolina, in which the SCOTUS decided, in an 8-1 majority, to loosen the Fourth Amendment a little more.

The case concerned a defendant who was stopped because of a broken brake light, even though North Carolina law requires vehicles to have only one working “stop lamp.” The defendant (unadvisedly) consented to a search, and the officer found cocaine.

With only Sonia Sotomayor dissenting, the high court reversed a lower court’s decision that the search was illegal because the original stop did not create a reasonable suspicion of a crime. Chief Justice John Roberts wrote that because the officer’s ignorance of the law was “reasonable,” the stop was not in violation of the Fourth Amendment.

The problem with this thinking is that it assumes beneficence on the part of all police officers. Even if most have the best of intentions, the few that don’t now have free license to unlawfully stop all manner of citizens — motorists or otherwise — and simply claim they made an honest mistake later. What happened to “ignorance of the law is no excuse?”

This decision doesn’t mean that the cops have the right to search us against our will, but it does mean that more of those who don’t know their rights will be duped into relinquishing them by dishonest cops. And remember, this can incriminate regular, honest, upstanding people, not just the underbelly of society.