One of the great inherent powers of the presidency is its power to set the national agenda -- "the bully pulpit," as Teddy Roosevelt called it. So when Donald Trump gazed across the political landscape, at difficult, complex issues such as North Korea, the devastation of Puerto Rico and the recovery of Florida and Houston, health care, tax reform -- where did he choose to focus the national conversation?

To the surprise of no one, he took aim at the actions of a small group of African-American athletes who for months now have engaged in a quiet and peaceful protest of police brutality against minority groups. They believe, with cause, that this great country, our country, is not living up to its promises and its best values, and by taking a knee during the national anthem, they have found a way to communicate that belief.

Despite all that, Trump claims that "this has nothing to do with race."

"I never said anything about race," as he put it Sunday. "This has nothing to do with race or anything else.”

Yet it is all about race, and he knows it. He chose the target for his disproportionate response, he chose the Alabama venue from which to launch this campaign, he chose the angry, accusatory language that was guaranteed to raise the temperature. He did all that because he knows instinctively where the fault lines run in American society, and how to cleave us.

It has been his sole claim to political genius. He knew precisely what it meant to claim for years that Barack Obama, our first black president, was not a real American but instead a Kenyan who thus had no right to be president. He knew the power of that message to black Americans and white Americans alike; he reveled in it and rode it to the Republican nomination.

He likewise knew the power of promising a ban on Muslim immigration, of the hatefully false claim that thousands of American Muslims had danced in joy after the attacks of Sept. 11, that Mexican immigrants are largely rapists and criminals, that there are very fine people among the neo-Nazis and white supremacists chanting "Jews will not replace us." He knew what all that would do.

So, in a speech Friday night in Alabama, he once again placed the wedge in the crack, drew back his sledgehammer, and drove it home.

“Wouldn’t you love to see one of these NFL owners, when somebody disrespects our flag, to say, 'get that son of a bitch off the field right now? He is fired!'?”

In the three days since, Trump has continued to hammer away at it on Twitter and elsewhere, and he has done so using language that is guaranteed to ensure that the issue remains inflamed. He doesn't ask or try to persuade or use reason. He demands complete submission to his orders, knowing that it is the one thing that his opponents will never give him. The NFL and its players "must respect" the flag and anthem, he says. The NFL "must tell them to stand." Those who choose to kneel instead "must be fired immediately." They cannot be "allowed" to keep doing this, and it is "not acceptable." They "have to respect our flag and have to respect our country."

Just to be clear, the players aren't spitting on the flag, or stomping on it or burning it. They aren't chanting or interrupting the singing of the anthem. By the simple, silent act of kneeling, they merely hope to force the rest of us to think about things that make us uncomfortable, that we would prefer to ignore because maybe, just maybe, they call into question whether this really is a country that delivers "liberty and justice for all?"

The NFL, to its credit, has decided that it will not submit to Trump, nor will it require its players to do so. In fact, some 150 players took a knee or raised their fists this weekend, and none will be fired. And if the target of the original protest has expanded to become Trump himself, well, he's fine with that too. I'm sure it pleases him to no end, because in his eyes it means his strategy is working.

He is using the symbols and rhetoric of patriotism to pit us against each other. By making us smaller, he can, for a while, make himself seem larger. But the damage that he is doing daily to the fabric of this country is almost incomprehensible.