Here’s the thing: You could detest everything Muhammad Ali stood for. You could rage at him for being a draft dodger, a Communist sympathizer, a coward. You could seethe at the swagger, at the braggadocio, at the times when he would reduce proud prizefighters to dust with his clever poetry.

“I ain’t got no quarrel with the Viet Cong,” he famously said in the 1960s, at a time when we believed the world was 15 minutes way from ending every time we lifted our heads off the pillow. “No Viet Cong ever called me n—–.”

You could hate him for that.

But the one thing you never could question, no matter how much you wanted to, was the legitimacy of his convictions. That was forever. That was something that will live for an eternity, long after we bid farewell to the man, to Ali, who died late Friday night after battling Parkinson’s Disease the final three decades of a most extraordinary life.

Ali paid for those convictions. He bled for them. At the height of his athletic prime, he refused to step forward and be called into the U.S. Army. He knew what that meant at the very moment he did it, April 28, 1967, at the Military Entrance Processing Station on San Jacinto Street in Houston.

He knew he would be hated. He knew he would be dismissed as a deserter and as a quitter, a turncoat who would refuse to submit to the draft. He knew.

He knew.

“Bravest thing I ever saw,” the great Jerry Izenberg told me once.

Izenberg — longtime sports columnist at the Newark Star-Ledger who also filled the pages of The Post with his wit, his wisdom and his biting social commentary for much of the 1980s, was a friend of Ali’s, but before that he was a defender of Ali’s, one of the first to accept his Muslim name in lieu of Cassius Clay, the “slave name” he was born with.

It was a lonely pursuit, standing for Ali in the late 1960s, after he was stripped of his heavyweight belt, after he was branded a traitor, after he couldn’t get a license to box in any of the 50 states for over three years. Izenberg walked that path with him, and so did Dave Anderson, and so did Howard Cosell, and so did Dave Kindred, working for Ali’s hometown Louisville Courier-Journal.

They were buffeted with the anger of the masses. It wasn’t an easy walk.

But Ali walked it loneliest of all.

On the morning after his death, that is what we should remember most of all, more than the time he flattened Sonny Liston, then did it again. More than the three primal wars he fought with Joe Frazier, the time the two of them christened the new Madison Square Garden in 1971 and the time, four years later, when they nearly killed each other in Manila.

“Frazier quit just before I did,” Ali said that night. “I didn’t think I could fight any more.”

The writer Mark Kram summed it up thusly: “They fought for the championship of each other.”

All of that explains the basic source of Ali’s fame, as does the gold medal he won in Rome in 1960, as does the time, 17 years later, when he first lost and then regained the title from Leon Spinks. He became the most famous athlete in the world because of the speed of his hands and the ferocity of his punches and the strength of his sporting will.

But he became a worldwide icon for something else, something that wasn’t comfortable for people to talk about in the ’60s, something that didn’t easily fit on the sports pages of the day, where sporting heroes thanked God and drank milk and spoke of the red, white and blue. That wasn’t Ali’s way and it certainly wasn’t his destiny.

So he refused induction. He refused Vietnam. He gave up his title, surrendered hundreds of thousands of dollars, became a pariah, and a proud one, and never once flinched, not even when he was broke and people had stopped paying attention. He wouldn’t be ignored. He wouldn’t be forgotten. He paid a steep price for his beliefs.

And only then did he become what he truly wanted to be.

The Greatest. Of all time.

This morning you can argue all you want about whether he was right to do what he did, to believe what he did, to act as he did. What you cannot debate — or ever debate — is if he was true to those beliefs, if he honored his conscience. He did. Forever.

Keep in your mind’s eye today his accomplishments, the beauty of his time inside a boxing ring, the champion’s soul that survived long past the point when his body surrendered to his disease. But keep in your heart what he did outside the ring. He demanded to be heard. He was heard. He suffered the consequences. And he survived.

Yes, he did. It is that light that will survive forever. It is that courage that will survive forever. You didn’t have to agree with Muhammad Ali, or even admire him. But you had to — have to — agree about this: He may have talked the talk better than anyone who ever lived.

But he damn sure walked the walk, too.

Outside the ring, Muhammad Ali had a beautiful way with words: