Speaking out about controversial political issues, even in the measured way he did yesterday, is extremely unusual for Obama. He went into his post-presidency reluctant to let Trump change him, or force him to abandon the presidential tradition, which he took seriously, of giving deference to one’s successors. He knows that, as the first black president, his words on race carry extra weight and attract extra attention—and, often, harsher judgment. But watching a president attempt to turn the firepower of the federal government against the American people helped him overcome his reluctance to intervene.

“He’s always said he’s going to speak out when (a) American values are threatened and (b) he can have impact,” an Obama adviser, who requested anonymity because they were not authorized to speak on the record, told me in an email. “This moment is both.”…

Obama’s hesitance to speak out on issues of race goes back to his own time in the White House, when his every utterance on the subject became something for pundits to yell about, from when he said the police officer who’d arrested Henry Louis Gates at his own home had been “acting stupidly” to when he said that if he had a son, “he’d look like Trayvon” Martin. In 2014, when another police killing prompted violent protests in Ferguson, Missouri, Obama took several days to respond. West Wing aides at the time defended the decision, bemoaning that everyone was turning to him because he was the first black president, insistent that he be able to just be the president—as in, the president for everyone. Obama was reluctant to let the polarization that followed everything he did make the situation worse. When he did speak, he denounced violence, spoke up for the police, and called for reforms. As he reminded those watching yesterday, he had a commission that studied police reforms.