I believe his reasons were purely strategic:

Mangione faced those charges in connection with the December 2024 shooting death of UnitedHealthcare CEO Brian Thompson.

“I shot Mr. Thompson in Manhattan and he died,” Mangione said in court Friday. “I knew what I was doing.”

Thompson’s family was in the courtroom sitting in the front row watching as Mangione entered his plea. Mangione voiced no remorse and repeatedly referenced his concerns with the U.S. health care system.

So he pleads guilty but admits nothing but the facts already known; there really wasn’t a scintilla of doubt that he stalked Thompson and murdered him in cold blood, shooting him in the back. He’s only sorry he’s been caught; he still is grandstanding to his leftist admirers.

Here’s the strategic part:

Mangione still faces murder charges in a state trial set to begin next month, but his guilty plea in federal court is expected to have significant impacts on the state trial. New York state’s strict double jeopardy law could potentially upend those proceedings. That law says that a defendant can’t be tried twice for the same thing.

Mangione’s defense team cited that law in a motion filed Friday, shortly after his federal guilty plea, urging state court Judge Gregory Carro to dismiss state charges against him, including a count of 2nd degree murder. If successful, that legal maneuver could spare Mangione a longer prison term.

Personally, I think even if he faces the state trial the jury will be hung, because some Mangione supporter or supporters will lie in order to get on the jury and hang it. In federal court that was far less likely, and that’s part of why he copped a plea.

State prosecutors aren’t giving up:

State prosecutors have argued their case is distinct, and that double jeopardy should not apply. In a statement to NPR, a spokesman for the Manhattan district attorney’s office said they would fight efforts by Mangione’s defense team to derail the state’s prosecution.

With guilty pleas, the sentencing is usually somewhat lighter than it would otherwise have been. The death penalty had already been ruled out for Mangione. Will he now get less than life? It’s certain possible, and sets a terrible precedent. If there was ever a cold-blooded and political assassination, it was this one.

Mangione cites his back pain as a motive:

“After years of enduring severe pain from a broken back and navigating the obstacles of the health insurance system, I learned that UnitedHealthcare would be holding its annual investor conference in New York City,” he said.

What a poor excuse. I have some experience with this; in my early forties I had a severe back injury and was in very significant chronic pain for at least twelve years. I spent a lot of money despite having health insurance, and most of the interventions did not work (unlike what happened to Mangione, whose back was fixed a couple of years after his injury by a fusion surgery). I was a participant in several chronic pain groups and listened to some very sad stories, and some angry people who were having major problems with the health care system. But never was anyone contemplating murdering some random health insurance executive. And by the way, Mangione’s insurance problems, whatever they might have been, did not involve Thompson’s company United Healthcare:

Luigi Mangione, the suspect accused of fatally shooting UnitedHealthcare CEO Brian Thompson in New York City last week, was not a customer of the private health insurer, but police say he had identified the company as one of the largest corporations in America in his “manifesto” writings.

Neither Mangione nor his mother were insured by UnitedHealthcare, the nation’s largest private health insurer, a UnitedHealth Group spokesperson told CNN.

“We have no indication that he was ever a client of United Healthcare, but he does make mention that it is the fifth largest corporation in America, which would make it the largest healthcare organization in America. So that’s possibly why he targeted that company,” NYPD Chief of Detectives Joseph Kenny said in an interview with NBC New York.

When Mangione first surfaced. I wrote a post comparing him to Dostoevsky’s Raskolnikov. I still consider the analogy a good one, except that Raskolnikov ultimately showed remorse and understanding. I don’t think Mangione is even close to that redemptive arc.