The Democrat debate on Wednesday was the undercard bout. The real Vegas fight — the one that matters — happens Saturday night.

Undefeated WBC heavyweight champion Deontay Wilder will face off against undefeated lineal heavyweight champion Tyson Fury in a rematch of their December 2018 fight, which ended in a thrilling draw.

This week’s political debate, feisty though it was, paled in comparison.

President Donald Trump is not expected to attend the fight, though he is in Vegas this week on a four-day swing through the west.

But the fight points to a fascinating story about his presidency.

Tyson Fury, the “Gypsy King,” is a fan of Trump, and invited him to attend the first fight in LA. The commonality more cultural than political: Fury is a “deplorable,” an Irish Traveller. He also likes to put on a show, and respects Trump as an entertainer.

Wilder, the “Bronze Bomber,” also likes Trump. But it was not always so.

In 2017, Wilder trashed President Trump as a racist.

The context was the president’s criticism of NFL players who knelt for the national anthem.

A journalist asked Wilder: “What is Donald Trump telling Black America when he calls football players like Colin Kaepernick ‘sons of bitches’ yet he’s not calling our police brutality that’s rampant — and we see it on YouTube all the time — what is he telling Black America?”

“He don’t give a damn about us. It’s plain as day. He don’t give a fu*k about us,” Wilder said in response. That’s not making America great again.”

But by 2018, Wilder was singing Trump’s praises. And the reason behind Wilder’s 180° turnaround on Trump could provide the key to the 2020 election.

Wilder came to the Oval Office to observe as Trump issued a posthumous pardon for Jack Johnson, the first black heavyweight champion, who was convicted of violating racist laws a century ago.

Somehow, President Barack Obama declined to do it. President Trump made it right.

“To be able to be here at the Oval office in Washington, DC, and to experience the ultimate pardon of Jack Johnson is amazing,” Wilder said. “Johnson was the first African American heavyweight world champion, so this was definitely a magical moment to remember and one that I never will forget. … Even though it’s almost 100 years too late, finally, justice has been served.

“A wrong was corrected for something that should never have happened, and of all of the presidents, Donald Trump was the one to do it.”

Wilder went from attacking the president — based on the “fake news” presentation of Trump’s position as being about racism rather than patriotism — to admiring him for correcting a historical injustice.

It was Trump’s words that had angered him, but it was Trump’s actions that finally won Wilder’s support.

There are millions of people across the country who feel the same way. They are told that Trump is a racist, that he is a bully. They are even told he is a threat to national security.

And yet when they see what he is doing, they see that the economy is strong, that the country is secure, and that racism is actually declining. America — despite deep and difficult challenges — is the best it has ever been, and getting better still.

That is not entirely because of Trump. It is largely because of the inherent goodness of Americans, and the basic drive of the American people to succeed — for ourselves, and for each other.

But it took a disruptive character like Trump to seize the unique opportunity of the presidency to find ways to push the country forward, to convince us that we could achieve more.

Trump’s rivals — who barely mentioned the economy or foreign policy in Wednesday night’s debate — promise to end the “noise,” the tweets, the combative political rhetoric.

But is that really the problem?

Earlier that afternoon, just down the street, Wilder and Fury were trash-talking up a storm — and the audience loved it. To fighters, the tough talk is part of the show — an important part, but hardly the essence of the sport.

When they lace up their gloves, all that counts is talent, preparation, and courage.

When Wilder met Trump, he saw beyond the talk. He saw through the fake news.

He saw what the president is actually doing for America. And he was amazed.

That’s the case Trump will make to the country in November.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He earned an A.B. in Social Studies and Environmental Science and Public Policy from Harvard College, and a J.D. from Harvard Law School. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.