We all know what makes a hero. Bravery. Conscience. Honor.

John McCain is a true American hero. He was shot down during the Vietnam War and tortured by the Viet Cong. When they discovered he was the son of an admiral, his captors offered to release him. McCain refused unless his fellow prisoners of war were also released. Five and a half years later, he came home, wounded but unbowed, entered politics, and has honorably served for three decades in Congress, four years in the House, and 30 in the Senate.

The Arizona Republican is now in his final battle. My mother had brain cancer, so I know how it goes. Judging from his recent interview on “60 Minutes,” so does McCain, and the 81-year-old accepts his fate with dignity and pride in a life well lived.

Just 11 days after brain surgery, McCain flew from Arizona to Washington to cast the deciding no vote on a slapdash health care bill he believed was rushed through.

Our president desperately wanted this bill passed to chalk up a win, and he belittled the senator. Indeed, McCain seems to hit a special nerve with him. Perhaps knowing he can never attain the bipartisan respect McCain garners, our draft-dodging commander in chief regularly attacks McCain, besmirching everything from his military service (“He’s not a war hero . . . I like people who weren’t captured”), to his vote on health care (“Disgraceful!”).

After the president recently mocked McCain at rallies in Alabama and elsewhere, many, including former Republican congressman and current cable host Joe Scarborough, reacted with disgust. “You have a man who is dying, and you’re using him for political punch lines?” Scarborough asked incredulously. “You have no humanity.”

I didn’t vote for McCain for president, but I would take him in a heartbeat over the national embarrassment now occupying the Oval Office. Our president can brag about his supposed billions, and stick his name on glitzy skyscrapers while stiffing the suppliers that helped build them, but he knows there’s one thing he can never buy: integrity.

McCain is the personification of class. And honor. And America. Thank you for your service, sir.

Playwright Mike Vogel blogs at newyorkgritty.net.