The shooter who … was interested in black-power groups and had black-nationalist stuff all over his Facebook page and who told cops during the standoff that he was upset at white people and wanted to kill some white cops as revenge for police shootings of black suspects?

Anyone want to help Harvard Law here tease out a motive?

Mr. Obama made the comment at a press conference in Warsaw, Poland, where he also issued another call for gun control in the wake of the Dallas shootings. “I think it’s very hard to untangle the motives of this shooter,” Mr. Obama said of the gunman, Micah X. Johnson. “By definition if you shoot people who pose no threat to you, you have a troubled mind.”

He covered his tracks a bit later in the presser by saying, “The demented individual who carried out those attacks in Dallas, he’s not more representative of all African-Americans than the shooter in Charleston was representative of white Americans.” Right, but that doesn’t mean the Charleston shooter didn’t have a discrete motive despite his “troubled mind.” In fact, Obama was astute in describing it at the time:

The fact that this took place in a black church obviously also raises questions about a dark part of our history. This is not the first time that black churches have been attacked. And we know that hatred across races and faiths pose a particular threat to our democracy and our ideals.

Correct. Dylann Roof is a white racist who wanted to kill blacks. And Micah Johnson is a black racist who wanted to kill whites. The country watched the chief of police in Dallas explain, on camera, not 36 hours ago that Johnson told the hostage negotiator that he wanted to murder white officers. As such, Obama playing dumb here will have the same effect as his dopey reluctance to use the term “radical Islam,” undermining Americans’ confidence that its leadership is looking clear-eyed at the causes of terrorism. He seems to believe on some level that to acknowledge an evil yet coherent motive for political violence is to risk legitimizing it. Either that or he’s convinced that when a member of a “vulnerable” group spills blood, the threat of a backlash against the group writ large is so ominous that the killer’s motive simply must be obscured to disrupt accusations of collective responsibility. (His Attorney General seems to share that opinion.) It’s a truism that people who murder for their prejudices have “troubled minds”: If that means we can never reliably know their motives then there’s no such thing, really, as political violence, just a bunch of slobbering lunatics wandering the landscape shooting at people — or flying 747s into buildings — for reasons even they only dimly understand. Literally no one believes that, including Obama. The left certainly doesn’t. And when a politician says something that literally no one believes, the already dangerously low reservoir of public faith in national institutions shrinks a little further.