NFL Commissioner Roger Goodell is on the verge of handing President Trump a significant political victory by calling on his players to stand for the national anthem.

For the first time since some players began taking a knee in protest of police misconduct, the commish officially and explicitly said he wants players to honor the anthem by standing — even as he respects their right to protest. He says the league will come up with a formal policy at next week’s owners meeting.

The question is: Why did the league finally cave?

The answer: Follow the money.

Trump is a rookie politician who makes rookie mistakes: He’s often impetuous and volatile, and those traits have certainly hurt passage of his broader agenda.

But the reason why he created one of the greatest brand names in the world — one he leveraged to become president — is that he has incredible marketing instincts. And he knows political correctness doesn’t sell to everyone.

With that, the NFL’s one-knee controversy, which was all but ignored by NFL brass before the president got involved, was an easy pick-six down the sideline for The Donald, who gleefully and expertly took advantage and scored some much-needed political points in the process.

The kneeling trend began last year with former 49ers QB Colin Kaerpernick as a protest against what he viewed as rampant police brutality against minorities. Initially, Goodell appeared to praise it as a way to move “from protests to progress,” but fans often booed what they saw as abject disrespect of a patriotic symbol.

(Goodell’s spokesman Joe Lockhart claims his boss has “always said he believes players should stand for the anthem.”)

Put aside the merits of Kaepernick’s blanket condemnation of the police; being PC can backfire on your bottom line. This is particularly true in the business of football, where the league and its teams make so much money leveraging the game to sell shirts, soft drinks, beer and a lot more mainly through TV advertising by appealing to a certain segment of the population: mostly male, largely white and middle class.

The league’s data, according to a source, show that around 70 percent of all NFL viewers make $100,000 a year or less. NFL viewers are nearly 70 percent white and mostly male. The typical viewer is also more likely to have served in the military than the general population.

In other words, welcome to Trump Country.

Trump knew this from the minute he started his stand for the anthem crusade a couple of weeks ago when he called the kneeling players SOBs at a political rally and then called on owners to throw the alleged SOBs off the field.

To be sure, much of the political cognoscenti thought Trump’s comments were rash throwaway lines — a little red meat to his base that wouldn’t amount to much more when all was said and done. Why, they wondered, would the NFL care what he said about players? No one knows how the typical football fan feels better than Roger Goodell & Co., right? Wrong.

Trump, ever the savvy marketer, does. In the aftermath of Trump’s comments, as his approval numbers rose (particularly among his base), the NFL’s numbers went down.

League numbers-crunchers combed through the data and discovered that despite some ratings improvements in recent weeks, game viewership is still way off compared to last year. Even worse, I am told, the league believes the social-media boycott by NFL viewers, angered by the disrespect they feel was not only directed at the flag and anthem but tacitly approved by the league, has the potential to grow exponentially if the NFL doesn’t make this issue go away.

As one NFL marketing executive told me: “All the data show that football fans are tired of being inundated with politics in a place they would like a reprieve from politics.”

Trump knew all this intuitively weeks before the NFL genius quants had any idea what was going on, and he outwitted some of the smartest people in the business.

He couldn’t have done this, though, without Roger Goodell, a good businessman with a PC blind spot. Example: The Dallas Cowboys wanted to honor five cops who were killed by a racist madman with decals on their uniforms. The NFL said no — it violated a decal policy.

Policy or not, what Goodell missed was a clear trend of stories that looked like his league was run by social-justice warriors. The fans, however, noticed — and so did the president.

Charles Gasparino is a Fox Business senior correspondent.