President Trump’s debate performance Thursday night just changed the course of this entire election.

On the day after the Presidential debate, most of the press’s focus is on the catastrophic performance of President Biden, who imploded before our eyes — looked old, hard to understand, confused, and resorted to mud slinging and name calling as the debate wore on and perhaps Mr. Biden realized he was digging a deeper and deeper hole for himself.

I don’t really blame the press for focusing on this — and the related question for the morning after, is how the Democrats are going to replace Mr. Biden.

But, and it’s a big but, Mr. Biden’s crash and burn should not obscure just how masterful Trump’s performance was. He kept his cool and had a straight chief executive-type demeanor. He was sharp and he was energetic.

His content on issues across the board that voters truly care about was superb. He crushed it on inflation, taxes, regulations, and jobs.

In other words, the positive, optimistic, prosperity, and opportunity message that is always a political winner.

In the early part of the debate, Trump pointed out that “the only thing” Mr. Biden “was right about is I gave you the largest tax cut in history. I also gave you the largest regulation cut in history. That’s why we had all the jobs.”

Mr. Biden was really helpless since the facts are so clear. He tried the usual lies about inheriting inflation and a disastrous economy, but Trump easily vanquished those arguments with some factoids and a strong narrative.

Trump clearly had done his homework. He was ready.

Mr. Biden spent a week at Camp David in an airplane hanger rehearsal twice a day with 16 or more advisers and was completely befuddled and unable to put two sentences together to defend his record in the face of Trump’s relentless attacks.

Many of us hope Trump will continue his campaign message that successful policies to grow the economy and keep the peace, would bring unity.

“My retribution is going to be success,” Trump explained. “What we did was incredible. We rebuilt the military. We got the largest tax cut in history, the largest regulation cut in history. The reason he’s got jobs is because I cut the regulations that gave jobs. But he’s putting a lot of those regulations back on all of the things that we’ve done.”

Time and again Trump returned to the issues of Mr. Biden’s border catastrophe and the related crime wave that has threatened public safety all across the country.

Again and again Trump talked about the border and the economy, his meat and potatoes. And Mr. Biden was unable to deal with it.

Then Mr. Biden starts slinging mud, calling Trump names, and of course bringing up January 6, 2021.

On this point, Trump delivered an absolutely brilliant response, which may well have been the most bone-crushing, game-changing moment of the debate night. 

“On January 6th,” he said, “we had a great border, nobody coming through a very few. On January 6th, we were energy independent. On January 6th we had the lowest taxes ever. We had the lowest regulations ever on January 6th. We were respected all over the world.”

At that point, the match should have been called off. It was a TKO — technical knockout.

And thereafter Mr. Biden literally sunk to grade-school name-calling and virtual gibberish.

On abortion, Trump was equally deft defending the Supreme Court decision to move the matter to the states and then the former president emphasized his view that to preserve exclusions for rape, incest, and life of the mother.

Then Trump correctly pointed out how radical and extreme the Democrats are on this issue. “The problem they have,” he said, “is they’re radical because they will take the life of a child in the eighth month, the ninth month, and even after birth, after birth.” 

He added: “If you look at the former governor of Virginia, he was willing to do this. He said, well, put the baby aside and will determine what we do with the baby, meaning we’ll kill the baby.”

 And then Mr. Biden launched into an incredibly offensive and irrational stream of consciousness about the dangers for young women. “And the idea that she was murdered by a by and by an immigrant coming in, they talk about that,” he said. “But here’s the deal. There’s a lot of young women to be raped by their father in laws, by the by, by their spouses, brothers and sisters, by or just it’s it’s just ridiculous.”

I have no idea what he was talking about or what the relevance was, or if it had anything to do with abortion, but Mr. Trump quickly riposted with the migrant crime wave which has swept the country as a result of Mr. Biden’s open border policy. And, unfortunately, we have seen all sorts of violence, rape, and murder.

And that stymied Mr. Biden even more. 

This debate will be a gamechanger, and will threaten Mr. Biden’s candidacy. The reality is that Mr. Biden was thrashed by Donald Trump on the issues.

Mr. Biden may have had a cold, he may be too old, he may be cognitively impaired — I can’t attest to any of those medical issues.

What I do know is this: the last two years in his campaign to return to the White House, Trump has emphasized issues of economic prosperity, higher take-home pay for working folks of all stripes and colors, closing the border, restoring public safety, and returning to an America First “peace through strength” foreign policy.

It’s an optimistic, mainstream, common-sense platform that is going to carry him back to the White House. You wait and see.

From Mr. Kudlow’s broadcast on Fox Business Network.