Twenty-four years ago, Robert Kosilek killed his wife. The Commonwealth proved its case. Bob got life in prison, throw away the key.

Guys in the big house don’t much like wife murderers. It goes easier if you’re in for tax fraud.

But it would get harder for Bob, because the boys at MCI Norfolk like transgendered folks even less.

In 2012, Kosilek, who had been living in prison as a woman, scored one on the Commonwealth. Her legal team used evidence and expert testimony to prove that gender reassignment surgery was medically necessary—as in, it was medically necessary for then-Mayor Thomas Menino to get a plate and screws put in his leg after he broke it last April.

Michelle Kosilek got approved for the surgery and the follow-up treatment that goes with it, and people got mad.

There are 47 million uninsured people in this country, reaching the middle class seems a Sisyphean crapshoot, and our government is bleeding treasure right and left.

Why in the hell did we approve a wife murderer for a free sex change?

Because it was the right thing to do, and because the Constitution demands it.

The Eighth Amendment doesn’t enjoy the cult-like enthusiasm heaped upon the Second Amendment (the right to bear arms) or the First (freedom of religion, assembly, and speech). But it’s important. It’s what prevents the government from imposing “cruel and unusual punishment” on prisoners. And it’s what federal district court Judge Mark L. Wolf used to order Kosilek’s surgery, because the words are right there on the faded parchment, and because denying an inmate—any inmate—a medically necessary procedure—any procedure—is the kind of medieval crap that goes on in North Korea, in Iran.

In January, a three-judge appeals court panel upheld Wolf’s ruling. Last month, the appeals court announced that the entire First Circuit Court of Appeals panel will rehear the case, a procedure often used when judges on the circuit find the case particularly important.

We needn’t regard the Constitution as infallible—it enshrined slavery and marginalized women—but the Framers got this one right. The Eighth Amendment is a necessary reminder that because criminal justice is administered by human beings, we sometimes wish to go too far.

For example, just this month, Gov. Deval Patrick disciplined several state corrections employees for the 2009 homicide of inmate Joshua Messier, a paranoid schizophrenic. While Messier was in handcuffs, guards folded his chest almost to his knees. Messier, 23, suffered a heart attack.

To an inmate, prison guards are God on Earth. They control everything you get. Food. Medicine. Protection from the hulk with that nasty habit of punching you in the teeth. Dental floss.

Back in 1976, citing the Eighth Amendment (and common sense), the Supreme Court ruled that prison guards’ deliberate indifference to an inmate’s serious illness constitutes unconstitutional cruel and unusual punishment.

When Godlike guards withhold needed medical care, that’s cruel and unusual punishment. You can’t do it.

And it’s a good thing that doctors, and not wardens, decide what’s medically necessary. Just like it’s good that judges, and not sheriffs, decide when police can search your house.

This is why we have professions: to keep amateurs from deciding things they don’t know jack about. If you’re not a doctor, you don’t know what’s medically necessary.

If Kosilek broke her leg and needed a plate and screws in it, no one would raise a finger to object to surgery. But a sex change? That’s over the line.

If you think this way, I have two questions: where did you go to medical school, and when did you become board certified in psychology?

With Kosilek, many fail to see beyond the repugnance of providing a murderer with surgery gratis. There is no public opinion data on Kosilek’s case, but her cause seems little more popular than the Bay State’s most infamous inmate, Dzhokhar Tsarnaev, who is accused of bombing the Boston Marathon.

Even progressive darling Elizabeth Warren criticized the surgery. “I don’t think it’s a good use of taxpayer dollars,” said the tenured law professor.

In an interview published last week by Boston Spirit magazine, Kosilek criticized Warren for Constitutional amnesia:

“It was disheartening to me — and that is the kindest word I can think of — that a sitting United States Senator could be so misinformed about the right to prison medical care as established by the Supreme Court decades ago. … You don’t lose your right to humanity and dignity when you go to prison. We don’t go to prison FOR punishment. We come to prison AS punishment.”

You can wish Kosilek a joyless life in prison and support her Constitutional right to medical care at the same time. In fact, you should.

Massachusetts liberals are proud that marriage equality—now unstoppable—got its big break in the Bay State back when the country hated the idea. It’s great that gay couples from the North End to North Adams can now marry. But Michelle Kosilek is part of the fight too.

It’s easy to stand up for LGBT rights when we’re talking about discrimination against loving couples. And it’s easy to stand up for the Constitution’s right of privacy when the NSA is spying on everything, everywhere, all of the time.

It’s easy to appeal to the Constitution when everyone agrees with you.

The real test is whether you point to that faded parchment on behalf of murderers whose gender identity doesn’t match their biological sex.

If Kosilek’s sexual reassignment treatment wasn’t necessary, it’s hard to see what treatment is. Tormented by life in a body that did not match her gender, Kosilek attempted self-castration and twice attempted suicide. At trial, doctors linked these macabre attempts to Kosilek’s gender identity disorder—which could be sufficiently treated only with gender reassignment.

In any event, medical treatment for the incarcerated is no Hippocratic ideal: a study published this month found that 40 percent of inmates leave jail with a serious medical condition, the majority of which were diagnosed in prison.

Truth be told, we do spend too much on medical care for inmates. But that’s because we imprison more people per capita than any nation on Earth. About 2.3 million Americans are behind bars. Blaming prison medical expenditures on Kosilek is like blaming Boston’s brutal winter on a single leaky cloud.

If you’re peeved that we’re spending too much on prison, look at the big picture. This story is bigger than Michelle Kosilek.

Said Kosilek in the Boston Spirit interview: “This is not about me.”

If you or yours is ever behind bars, you’ll know what she’s talking about.

[Photo: Lisa Bul/AP]