As Brian Doherty noted last night, it seems clear that Sandra Bland, who died by hanging in a Texas jail on July 13, would not have been arrested if she had not rebuffed a state trooper's request that she put out a cigarette after she was pulled over for changing lanes without signaling. But smoking in your own car is legal in Texas, so what offense did Trooper Brian Encinia think Bland had committed when he declared that she was under arrest?

In the dashcam video of the encounter, Bland repeatedly asks Encinia why he is arresting her, and he never gives a clear answer. Although she was charged with assaulting a police officer, the supposed assault occurred after Encinia announced that she was under arrest, forced her out of her car by pointing a stun gun at her, and handcuffed her. So what was the initial justification for arresting her?

Possibly Encinia had in mind Chapter 542, Section 501 of the Texas Statutes, which says "a person may not willfully fail or refuse to comply with a lawful order or direction of a police officer." In the video Encinia repeatedly says Bland has refused to comply with his lawful command to exit the vehicle, which is what leads him to threaten her with his stun gun, saying, "Get out of the car! I will light you up. Get out!" Bland says he has no legal right to demand that she leave her car based on a minor traffic infraction. Encinia insists he does have that authority.

Sadly, Encinia seems to be right, thanks to Pennsylvania v. Mimms, a 1977 decision in which the U.S. Supreme Court said a police officer may order a legally detained motorist out of his car at will. The case involved a man named Harry Mimms, who was stopped by Philadelphia police for driving a car with expired tags. After Mimms was ordered out of his car, the officer noticed a suspicious bulge under his jacket that turned out to be a gun. Mimms was charged with illegal possession of a concealed firearm, and he tried to have the gun excluded as evidence by arguing that it was obtained in violation of the Fourth Amendment's ban on "unreasonable searches and seizures." The Pennsylvania Supreme Court agreed, saying the officer needed some specific reason, beyond the traffic violation that resulted in the stop, to force Mimms out of his car. The U.S. Supreme Court disagreed, saying general concerns about officer safety are enough to justify such an order:

The State freely concedes the officer had no reason to suspect foul play from the particular driver at the time of the stop, there having been nothing unusual or suspicious about his behavior. It was apparently his practice to order all drivers out of their vehicles as a matter of course whenever they had been stopped for a traffic violation. The State argues that this practice was adopted as a precautionary measure to afford a degree of protection to the officer, and that it may be justified on that ground. Establishing a face-to-face confrontation diminishes the possibility, otherwise substantial, that the driver can make unobserved movements; this, in turn, reduces the likelihood that the officer will be the victim of an assault. We think it too plain for argument that the State's proffered justification—the safety of the officer—is both legitimate and weighty…. The hazard of accidental injury from passing traffic to an officer standing on the driver's side of the vehicle may also be appreciable in some situations. Rather than conversing while standing exposed to moving traffic, the officer prudently may prefer to ask the driver of the vehicle to step out of the car and off onto the shoulder of the road where the inquiry may be pursued with greater safety to both. Against this important interest, we are asked to weigh the intrusion into the driver's personal liberty occasioned not by the initial stop of the vehicle, which was admittedly justified, but by the order to get out of the car. We think this additional intrusion can only be described as de minimis.

Encinia apparently did not have a general practice of making drivers get out of their cars, as you can see in the traffic stop that preceded Bland's. Furthermore, he did not tell Bland to get out of her car until she refused to put out her cigarette, saying, "I'm in my car. Why do I have to put out my cigarette?" Maybe Encinia had a safety concern related to secondhand smoke. More likely, he was annoyed by what he perceived as Bland's failure to respect his authority. He later told her that he had been ready to let her go with a warning and that she had only herself to blame for the way the encounter ended.

Others disagree, as The New York Times notes:

State legislators who saw the video…just before it was publicly released sharply condemned the officer's behavior, which the director of the Texas Department of Public Safety, Steven McCraw, said was a violation of department arrest procedures. State Senator Royce West, Democrat of Dallas, said Ms. Bland, 28, should never have been taken into custody. State Representative Helen Giddings, Democrat of Dallas, said, "This young woman should be alive today."

The Texas Department of Public Safety says Encinia, who has been assigned to administrative duties while the arrest is investigated, "violated the department's procedures regarding traffic stops and the department's courtesy policy," although it's not clear exactly what that means.

Based on their comments in the video, Encinia and Bland clearly agreed that the escalation from warning to arrest was ridiculous, but they had diametrically opposed views of who was to blame. If only Bland had been more respectful and cooperative, Encinia thought, she could have been on her way. If only Encinia had not been so determined to assert his authority for its own sake, Bland thought, he never would have forced her out of the car, let alone handcuffed her and knocked her down.

They were both right. Knowing that police work tends to attract more than its share of authoritarian bullies, Bland could have hidden her annoyance at being pulled over after switching lanes to let Encinia pass. She could have meekly complied with his instructions, in which case she probably would still be alive (whether or not she actually killed herself in her cell, as a coroner concluded, or was the victim of foul play, as her family suspects). But it is hardly surprising than an activist against police abuse would bridle at the expectation that she simply do as she was told, even though that expectation has been endorsed by the Supreme Court.