To send George Zimmerman to prison for what happened would be an act of vengeance, not justice.

That the prosecution in the Zimmerman trial asked the judge to allow a verdict of “third-degree murder” — i.e., child abuse, since Trayvon Martin was 17 — testifies to the prosecution’s failure and panic.

For George Zimmerman’s defense has proven, beyond a reasonable doubt, that he shot Trayvon Martin not out of malice, rage or hate — but in a desperate act of self-defense.

Zimmerman was being beaten “ground-and-pound,” mixed martial arts style. His head was being banged on the cement. Screaming again and again for help, he pulled out his gun and fired.

Even the prosecution is now conceding Trayvon might have been on top, and is now scrambling for a compromise verdict on a lesser charge than second-degree murder, a charge that never should have been brought. Indeed, this trial should never have been held.

What we have witnessed in Sanford, Fla., is the prosecution of an innocent man for murder because the politically and socially powerful demanded it.

That Trayvon is dead is a tragedy, and an avoidable tragedy. But it was not murder. And it does not justify railroading a man who, whatever his mistakes that night — and George Zimmerman made them — committed no crime.

The case comes down to four questions. And the answers, supported by the evidence, testimony and common sense, point straight to an acquittal.

First, who was the aggressor?

All agree it would have been better if Zimmerman had never left his car or followed Trayvon that night.

Yet, ask yourself:

Would a pudgy, out-of-shape 28-year-old with a gun, facing a 17-year-old athletic kid, 4 inches taller, with a longer reach, throw a punch and start a fistfight with him?

If Zimmerman threw the first punch, what would be his motive? If you have a gun and your adversary does not, is not the sensible stance to keep your distance so you can be free to pull the gun? Who armed with a pistol starts a fistfight with a suspicious stranger?

Moreover, Trayvon’s body showed no signs of having ever been punched, while George’s nose looks like he was sucker-punched.

Second, who was on top in those final moments of the fight?

If Zimmerman was on top and Trayvon was on his back, Trayvon would have been found on his back. He was found dead on his stomach.

If Zimmerman was on top and Trayvon was on his stomach, he would have been shot in the back. He was shot in the chest.

How could Trayvon have been found lying on his face, with a bullet hole in his chest, if Zimmerman was sitting on top of him? Only if George Zimmerman, after shooting Trayvon, would have turned him over as he lay dying. No one has even suggested that.

Why was the back of Zimmerman’s jacket soaking wet, and the back of Trayvon’s dry, if Trayvon was on the bottom? Why were the knees of Trayvon’s pants wet, if he was on the bottom?

Third, who was screaming for help?

His mother, brother and father say it was Trayvon. George’s mother, father and half a dozen friends say it is George’s voice on the tape, screaming for help.

Trayvon’s father and brother apparently told investigators initially that the voice was not Trayvon’s, or they did not know. And the eyewitness John Good says the guy on the bottom in the red jacket, George Zimmerman, was the one screaming.

But, again, let us assume it was Trayvon screaming.

Why would he be screaming? If he was being beaten up martial arts style on the ground, would Trayvon not have had cuts and bruises?

What, exactly, was George Zimmerman doing to this 17-year-old football player that he should be screaming for help?

Where is the physical evidence that Trayvon had been hurt in any way before he was shot? Is screaming how a tough 17-year-old male reacts in a fistfight, even one he is losing?

Trayvon was a stranger in that neighborhood, and George was the neighborhood watch guy. Which of the two is more likely to be yelling for help from the neighbors?

Fourth, was the use of a firearm justified, even if Zimmerman was losing the fight and being beaten up?

Were his injuries that serious? Was he really is danger of grave bodily harm?

Experts disagree. But the real question is: What did Zimmerman think at the time? And judging by those piercing screams, was not that screaming man frightened, even terrified?

Trayvon’s parents think these were the desperate cries for help of a son about to be killed. But if they were Zimmerman’s cries, could George not have had those same thoughts?

George Zimmerman should have informed Trayvon he was the neighborhood watch. Trayvon should not have pummeled him. Both made mistakes. One is dead. To send the other to prison for what happened that night would be an act of vengeance, not justice, an invocation of the old lex talionis — an eye for an eye.

That’s not what America is supposed to be about.

Patrick J. Buchanan is the author of “Suicide of a Superpower: Will America Survive to 2025?”