Perhaps boxer Mike Tyson best explained fallen presidential kingmaker Steve Bannon’s about-face decision to testify before the U.S. House of Representatives Jan. 6 Select Committee.

“Everyone has a plan,” Tyson once said, “until they get punched in the mouth.”

Bannon, who always presents himself as the moxie and muscle behind Donald Trump’s rise to the Oval Office, saw himself as a guy with lots of plans who knew how to throw a punch. He just hasn’t shown that he can take one.

Bannon preened like a world-beater after he and Trump won the 2016 presidential election. They neatly overlooked the fact that they barely defeated a weak Democratic nominee and still managed to come up 3 million popular votes short in the final counting.

A narrow escape such as that one would have persuaded anyone with a modicum of intelligence to change tactics once in office.

Not Bannon, who morphed from being a self-proclaimed campaign guru into a sort of all-purpose political and national security adviser once Trump was installed in the White House.

He was the architect of Trump’s aggressive attempts to alienate anyone who didn’t agree with him all the time. Bannon drove suburban country-club Republicans who supported the GOP because they like low tax rates into being first independents and then soft Democrats because they didn’t want to be party to pogroms and other forms of persecution.

He took what should have been a winning hand — a rising economy and relative peace — and turned it into a formula that cost Republicans the House of Representatives in 2018 and expanded Trump’s popular vote deficit by another 4 million in 2020.

A large part of the problem was Bannon’s limited but belligerent view of the world. A self-proclaimed “white nationalist” — more on that in a moment — he gloried in the wars of identity politics. He was convinced that if he just rallied all the white Americans who felt aggrieved by the march of time and historical forces to his and Trump’s side, that would be enough to carry them to victory.

As a mathematical proposition, Bannon’s strategy was flawed from the beginning. Demographic trends have made the white vote a force of decreasing power for decades.

In 1988, Republican George H.W. Bush captured 59% of the white vote and that was enough to give him a landslide victory over Democrat Michael Dukakis. Just 24 years later in 2012, Republican Mitt Romney also claimed 59% of the white vote and took a shellacking from Democrat Barack Obama.

The difference between those two elections a quarter-century apart was that America’s non-white population has grown dramatically, a fact that made a “whites-only” approach a long-term loser from the start. If not for anomalies in the way electoral votes are counted, Bannon and Trump would have had their heads handed to them in 2016.

But the more fundamental problem with Bannon’s approach was its sheer idiocy. His understanding of both history and geography is about as deep as a summer puddle in the desert on a scorching day.

He presumes that skin color — race — drives everything.

But that is to assume that the French and the Germans — who fought three savage wars against each other in less than a century — have exactly the same take on things. Or that the Swedes and the Italians see the world in identical fashion.

It also ignores all the other historic and cultural forces — religion, economics, etc. — that have divided humanity through the ages.

The severely curtailed limits of Bannon’s world view prompted one observer to describe him as the sort of guy “who thinks because he’s read one book, he’s read them all.”

Bannon’s grandiose combination of arrogance and ignorance did a superb job of shrinking the Trump circle. He started quarrels not only with Trump’s opponents but also his friends — and, finally, with Trump’s family.

Bannon’s criticisms of the former president’s children got him ousted from the White House.

Bannon went down whining, leaking and complaining to writer Michael Wolff and others that the Trump kids were mean to him.

That’s quintessential Steve Bannon. He’s the sort of guy who loves to start fights and never sticks around to finish them.

Now, under threat of spending two years behind bars on contempt charges, he’s dropped his resistance to testifying before Congress.

Doubtless, Bannon has a plan.

We’ll see how that goes.