That’s what he did. Trump saved the national anthem.
What, you really thought these protests were about solidarity with Colin Kaepernick’s right to protest? What do you think Kaepernick was protesting? What do you think anyone who refuses to stand for the National Anthem is protesting?
Are they protesting some undefined view of America, as a factory of white privilege, dream-stealing, rich people enslaving the interests of poor blacks? Is that what the millionaires who play for the NFL are protesting? Are they protesting some unfair system that prevents people from getting ahead, when the NFL’s rosters are 70 percent black?
No. They are protesting symbols. And the symbol Kaepernick and those who support him have chosen is the National Anthem. They want it removed from sporting events. After all, it’s not a law that the anthem has to be played before all American sports events. It’s just tradition. And tradition, for progressives, is the enemy. If a progressive happens upon a fence with a gate, he does not ask why the fence is there, or who put it there. He simply labels the fence-builder as an oppressive racist and removes the fence, the gate, and any evidence they were ever there.
Progressives have defaced a statue of Francis Scott Key in Baltimore, not because of Key (who himself was a minor historical figure), but because of the anthem he wrote.

"Racist Anthem": The century-old Francis Scott Key Memorial at Eutaw Place in Baltimore was defaced overnight. https://t.co/nWTa2thxX2 pic.twitter.com/5vPAqNyTeT

— Colin Campbell ☀️ (@cmcampbell6) September 13, 2017

It’s the anthem they want removed from public life. They have started their biggest push with the NFL, spurred on by Kaepernick, and his subsequent status as too hot to handle by any NFL team. They’ve smuggled the “kill the anthem” goalposts into a “stand with Colin” argument.
President Trump called them out. He ignored Kaepernick and went right for the anthem. Standing for the anthem means the anthem stays. Sitting, kneeling, staying in the locker room, means the anthem is doomed. If Trump had not said anything, it’s likely that at least one team would stop playing the anthem before its games, to show “sensitivity” for the players who find it offensive. Then two teams, then all the teams.
And, poof, just like that, the National Anthem is gone from football. Then possibly baseball, or basketball, or hockey (but not NASCAR).
You say that’s ridiculous? That’s what we all said about traditional marriage being redefined in the 1990s. That’s what we said about a Christian being forced to cater a gay wedding in the early 2000s. That’s what we said about corporate executives being forced from their jobs over a political donation made years before to support traditional marriage. That’s what we said when the will of the people in California was overridden by a closeted gay judge for his own personal opinion to eliminate traditional marriage. That’s what we said before the Supreme Court did the same to the wills of people all over the country.
This nation is not the same place it was even thirty or forty years ago. But we are all tied together by certain threads of Americana: our flag, our anthem, our Constitution, our art, our achievements, and the beliefs set forth in the Declaration of Independence. Piece by piece, progressives would like to see those threads broken, so they can implement their unending quest to change, overthrow, only to overthrow again.
By making a stand from the highest political office in the land, Donald Trump stopped this thread from breaking. The NFL would now break before the anthem. Had Trump not have spoken and made this an issue,  that would not be true.
You might think that, compared to North Korea, Iran, health care, the national debt, antifa and white supremacists, that kneeling or sitting for the National Anthem at NFL games is a small issue. And it is, but from the standpoint of history, losing the National Anthem is not a small issue. The sitting and kneeling would eventually lead directly to the anthem’s demise. I say it’s better this is nipped in the bud and called out for what it is before it’s too late.
Once the anthem is lost from sporting events, it would never be regained. These kinds of small battles sometimes win the big wars.
So, thank you Donald Trump. You are fighting a small battle, and it may just help win the big war against the memory hole of progressivism.