By Josh Voorhees

A Staten Island grand jury on Wednesday declined to indict Police Officer Daniel Pantaleo in the death of Eric Garner, an unarmed man who was killed this summer when an officer used a choke hold to restrain him. "The grand jury kept interviewing witnesses but you didn't need witnesses," Garner's widow told the New York Daily News, referring to the fact that her husband's death was caught on camera. "You can be a witness for yourself."

The decision comes a little more than a week after a St. Louis County grand jury also declined to indict Darren Wilson, the officer who shot and killed Michael Brown in Ferguson, Mo. It's impossible not to pair the two cases. Both involved a white officer who took the life of an unarmed black suspect. Both prompted public demonstrations that forced authorities to press forward with legal proceedings they might not otherwise have undertaken. Both featured a protracted grand jury hearing that saw the defendant take the witness stand to tell his side of the story. And both concluded with the jurors deciding there was not enough evidence to indict the officer.

As frustrating as the grand jury outcomes may be, neither should come as a surprise. The default setting for our criminal justice system is to believe that an on-duty officer who takes another citizen's life was justified in doing so. Unless that baseline assumption changes, we should expect the same result the next time a cop takes someone else's life in the line of duty. Even when the killing is caught on video. Even when the police officer uses a choke hold that's been barred by his department.

The lack of serious second-guessing of police behavior is baked into the system at all levels. Our laws give officers broad leeway to use force, either when they fear their lives are in danger or when they are making an arrest. The Supreme Court cemented the scope of that authority in 1989's Graham v. Connor, in effect barring courts from scrutinizing most of the split-second decisions a cop makes in the heat of the moment.

Pantaleo's decisions were caught on camera. The cellphone video shows Pantaleo placing Garner, who police allege was illegally selling cigarettes, in a choke hold after he resisted the officer's attempts to put his hands behind his back. Garner is then forcibly taken down and pinned to the ground by a handful of cops. An asthmatic, he can be heard on the recording uttering what would turn out to be his final words: "I can't breathe."

Pantaleo contends that he didn't use a choke hold - he says it was a takedown maneuver he was taught by the police department. With the exception of the police union, no one seems to have bought that claim. "It looked like a choke hold to me," New York City Mayor Bill de Blasio said after viewing the video. The coroner's report ruled that Garner's death was a homicide caused by "compression of neck (choke hold), compression of chest, and prone positioning during physical restraint by police." That's important. NYPD officers have broad authority to use force to apprehend a suspect, but the department bars officers from using choke holds.

City officials restricted the use of the maneuver in 1985 - allowing it only when an officer's life was in danger, and it was the "least dangerous alternative method of restraint" - before banning it in 1993. Then-Chief John Timoney summed up the policy: "Basically, stay the hell away from the neck." Still, Timoney said he could imagine "extreme circumstances" in which an officer might have no other choice but to break the rule.

There is no indication that this case involved "extreme circumstances." The officers' lives did not appear to be in danger, nor is there anything to indicate that Garner is attempting to flee. While the video does suggest that Garner was unlikely to be taken into custody quietly, he resists arrest only in the strictest sense of the term. He can be heard yelling, "Please, just leave me alone!" and, eventually, attempts to keep the officers from forcing his hands behind his own back. But Garner was unarmed and does not strike any of the officers as they take him to the ground.

Why then, if choke holds are banned, wasn't Pantaleo indicted? While the officer's use of the maneuver received significant scrutiny in the court of public opinion, it likely received much less in the court of law. As Eugene O'Donnell, a professor at the John Jay College of Criminal Justice, argued earlier this week, there is a difference between an act that is banned by the NYPD and one that is deemed criminal. "There is no explicit law that criminalizes the use of a choke hold on someone either by a police officer or someone else," wrote O'Donnell.

Grand-jury proceedings happen behind closed doors, so we may never know exactly what convinced at least 12 of the 23 jurors to vote against an indictment. But by deciding - despite the video - that there was not enough evidence to justify the case going to trial, the jurors are effectively declaring that Garner's death was, at worst, a horrible mistake, one that might amount to misconduct but that falls short of murder or manslaughter.

The only reasonable way the jurors could come to that conclusion is if they focused on the twin questions of intent and expectations. When Wilson fired his weapon at Brown in Ferguson, the officer knew the likely fatal outcome. It's tougher to say whether Pantaleo should have reasonably expected his choke hold to end Garner's life. "It is never my intention to harm anyone, and I feel very bad about the death of Mr. Garner," the officer said in a prepared statement following Wednesday's announcement.

With the system we have in place, Pantaleo's assurances could have been all that was needed to convince the grand jury. In the United States, cops get the benefit of the doubt in almost all circumstances. If you believed that a case where an unarmed man was choked to death might be a rare exception to that rule, then you were wrong.

Josh Voorhees is a Slate senior writer. josh.voorhees@slate.com