There were five arguments for not executing murderess Theresa Lewis, who just became the first woman put to death by Virginia in almost a century. Four of the arguments were flawed, but one was not. And one should have been enough to save her life.

The first argument is, of course, the position that capital punishment itself is wrong in all cases. Most people who claim to hold this belief really don’t, and will admit that certain individuals, such as Osama bin Laden, or Adolph Hitler, really do deserve to be executed. The problem with not having an ultimate punishment for something—whatever act or acts society decides are the worst offenses imaginable—is that it inevitably softens the perceived offensiveness of all crimes, as we see in Europe. Penalties flow down from the worst crimes to the least…if killing a cop, or slaughtering a family, or betraying one’s country only warrants life imprisonment, then a single murder, no matter how cold-blooded, will eventually earn a lesser sentence than life. The end-result is to diminish the strictures and cultural consensus against all crimes. It doesn’t matter if we reserve the death penalty only for diabolical serial killers, traitors and mass murderers ( a recent study argues that Mao ought to be “credited” with 45 million murders—is that enough to warrant an execution?); the point is that society needs to declare what it considers the worst crimes, and allot punishment accordingly, with the death penalty making the most powerful statement possible.

The second is that Theresa Lewis was a woman. Even death penalty advocates wince at executing women, but this is only a gag reflex from an earlier time. Women made a compelling and winning case for their equality, and they, as well as the rest of us, should reject any double standard. A man who did what Lewis did (she plotted to kill her husband and stepson to collect insurance money) would be seen as an obvious candidate for death row. Gender bias, like racial bias, needs to be purged from the criminal justice system. [The Supreme Court turned down her appeal; only female Justices Sotomayor and Ginsberg voted in favor of it.]

The third argument was that Lewis underwent a post-conviction conversion, showing remorse, compassion and a gentle, nurturing side in prison. Sorry: too little, too late. Convicted killers are not executed for what they might do in the future, but for what they have already done. The claim that a condemned man or woman “is not the same person” as the one who did the crime is intellectually dishonest as well as irrelevant. I have little doubt that knowing one is about to die can bring about epiphanal  conversions, but unless it creates the ability to resurrect the victims, this is a weak argument for mercy.

Then there is this: Lewis’s measured I.Q. was just two points short of the Supreme Court standard, articulated in the Atkins case, where it ruled that a prisoner’s mental retardation makes execution “cruel and unusual punishment.” I don’t disagree with the proposition that at some point an individual’s lack of mental capacity ought to preclude inflicting society’s ultimate punishment. The question is what that point is. The Supreme Court made 70 its cut-off; that may arbitrary, but cut-offs are unavoidable and necessary. If we decide that a 70 I.Q. cut-off can be rounded up to 72, then the killer with a 73 I.Q. has the same argument, and onward up the scale, until Stephen Hawking is found too mentally deficient to execute. There are also equality issues involved here, as with women. We have come a long way in recognizing that those with below-average mental capabilities should be allowed to live independent lives, marry, and hold responsible jobs. The right to be treated like every other American also includes the presumption that one is capable of meeting a citizen’s basic duties, like obeying the law. The mentally challenged cannot simultaneously insist on equal opportunities and treatment by others without also accepting an equal measure of accountability. Are most Americans with I.Q.’s of 72 or higher able to negotiate life without murdering their families? Should we trust them to have enough autonomy that they might kill them if they chose to? If the answers to these question are yes—and they are—then Lewis’s mental acuity should not have been a reason for treating her differently from other murderers, and those with similar disabilities should applaud her execution. It is a demonstration of respect for all of them, even though it had an unfortunate result for one of them.

The final argument for Lewis, however, ought to have saved her life. After Lewis confessed, pled guilty, and was sentenced to death, the two men she paid to shoot her husband and son were sentenced to life imprisonment. One of them, in a letter to his girlfriend before he killed himself in prison, said that he had used Lewis, whom he knew was intellectually weak and easily manipulated, because he wanted money to go to New York and become a drug dealer. Though he was far from a genius, tests showed that Matthew Shallenberger was approximately 50% more intelligent than Lewis, who regarded him as her lover. There is no question that Lewis was an active participant in the crime; she gave the men cash to buy guns and left the door unlocked the night of the shootings. Still, Shallenburger’s admission made the fact that he and Rodney Fuller, the other shooter, got life sentences while Lewis was sentenced to die a clear instance of injustice.

Virginia Governor Bob McDonnell should have commuted her sentence to life without parole, not because she was a woman, and not because of her low I.Q., but because there was ample evidence that she was exploited and manipulated by the real architect of the plot, who was spared a death sentence. This factor means that Theresa Lewis was far from the worst of the worst; indeed, she was not even the worst conspirator in the crime she was sentenced for. She didn’t deserve to die, and it was wrong for Virginia to kill her.