Sandra Bland was pulled over for failing to signal while changing lanes. A lot of readers have watched the traffic stop which led to Bland's arrest for assaulting an officer. If you haven't, you should.

The Bland video brings up an overlooked problem with the law of police-citizen encounters. The police can back up their orders with force because it's often a crime to disobey a lawful order from a police officer. But from a citizen's perspective, it's often impossible to know what is a lawful order. As a result, it's often impossible for citizens to know what they can and can't do during a police encounter.

The first problem is knowing what counts as an "order." If an officer approaches you and asks you to do something, that's normally just a request and not an order. But if there's a law on the books saying that you have to comply with the officer's request, then the request is treated as an order. You can't know what is an "order" unless you study the law first, which you're unlikely to have done before the officer approached you.

The even bigger problem is knowing when an order is "lawful." An order is lawful if forcing compliance would not violate any law. But a citizen is in no position to assess that. Even if the police pulled over the world's greatest legal expert, the citizen still couldn't know what orders are lawful because the laws often hinge on facts the citizen can't know. – Washington Post, July 23, 2015

Today's excerpt is by Orin Kerr, a George Washington University law professor. The Sandra Bland arrest video he discusses will – or at least should – outrage anyone who respects justice and decency. The way the officer repeatedly screams, "I'm giving you a lawful order" suggests he defines "lawful" as "subservient to me."

Still, Professor Kerr brings up a troubling quandary. It simply isn't possible in most situations for a citizen to know whether a police order really is lawful. As a practical matter, our only choice is to either 1) comply without question or 2) face arrest and hope a judge will show mercy.

This dilemma is inconsistent with the supposedly "free" society the United States claims to be. Police have an open opportunity to abuse their authority, and many do. That they would especially abuse those they perceive as less worthy of respect is also no surprise. That is what bullies do. They learn on playgrounds in early childhood that the best way to hide their own fear is to oppress weaker children.

The only reason we can see the Sandra Bland arrest video is that she subsequently died in jail. Such bullying happens all over the country every day of the year. Even cameras don't stop it. The Texas state trooper who stopped Sandra Bland knew he was on video, but seemed not to care.

While other politicians and bureaucrats may not carry guns or use violence, everything they do carries the same implicit threat. We are all in the same position as Sandra Bland every time we open a letter from the IRS or get a call from a "child welfare" agency. If we don't face the state's raw power in person, we still face it from a distance.

Sandra Bland dared to protest and resist the government's claim to control her life. As a result, she lost her life. Any of us could lose ours, too. State violence is a threat to everyone.