The Petite Policy, named for the Supreme Court’s decision in Petite v. United States, prohibited federal prosecution of a defendant who had already been prosecuted for the same offense by the state in the absence of a strong demonstrable federal interest that went unvindicated. While the Double Jeopardy Clause didn’t apply under the Dual Sovereigns Doctrine, the policy precluded overbearing and unnecessary federal “piling on” when the defendant had already been punished for his acts. While the policy was vague and voluntary, the idea behind it was good, as it prevented prosecution that violated the spirit, if not the doctrine, of double jeopardy.

But that was back when the DoJ cared about such matters, and when federal prosecution was the superior mechanism for assuring that crime would not go unpunished or insufficiently punished due to state parochial concerns or bias.

In a New York Times op-ed, Columbia Lawprof Tim Wu tacitly reversed the Petite Policy by calling for states to prosecute federal defendants convicted but pardoned by Trump.

A disturbingly large number of well-connected and wealthy felons have been pardoned by Mr. Trump, in some cases after they reportedly spent hundreds of thousands or even millions of dollars to support Mr. Trump’s re-election efforts or to attend a dinner at Mar-a-Lago or to pay politically connected lobbyists or associates of Mr. Trump to help get clemency. All of which fosters the impression that the president’s friends and donors are above the law.

Because the exercise of the president’s pardon power is highly discretionary, it might seem that nothing can be done. But there is a solution hiding in plain sight: The states can and should collectively work to hold people responsible when the federal government will not — by prosecuting those who were wrongfully pardoned.

The president’s pardon power is not merely “highly discretionary,” but unreviewable. No matter how corruptly it may be used, it’s the president’s power without oversight or challenge. And since it’s a core presidential power, the president would be immune from prosecution even if he openly and notoriously abused the power by taking bribes for pardons. The optics might be bad, at least to some of us, but there isn’t a damn thing to be done to the president for this act of corruption.

That doesn’t mean, however, that the pardon-buyers (or the cash paid) can’t be reached.

People routinely forget that the states, as separate sovereigns, have the power to bring cases that the federal government has abandoned or declines to prosecute, so long as the conduct in question violates state law. And state prosecutions are unaffected by federal pardons.

It’s a little more complicated than Wu makes it seem. There are jurisdiction and venue issues. There are evidentiary problem when the states don’t have access to the admissible evidence needed to pursue a prosecution. And then there are some states, like New York, whose double jeopardy laws are broader than the federal governments, and preclude a second prosecution even if the Double Jeopardy Clause would allow it.

But then there’s the Chesterton’s Fence problem. Sure, it’s easy to call Trump’s pardons corrupt because, well, he doesn’t even bother to hide his malfeasance as he makes it clear that you can either buy a pardon or rest easy knowing that crimes you commit in furtherance of Trump’s interests will be rewarded with a “get out of jail free” card.

Mr. Trump has not been subtle in the message he is sending: that the law is for other people. This is not only corrupt in individual cases; it also fosters corruption more broadly. Once word gets out that undeserving pardons can be bought or lobbied for, the law loses its deterrent effect.

Once the door is opened to states prosecuting defendants pardoned by the president, what limiting principle will apply when it goes beyond those corruptly pardoned by Trump to those defendants hated by a state for the nature of their crime?

Of course, some people who receive presidential pardons are deserving of clemency. Those people should not be prosecuted by the states, and in borderline cases, states should err on the side of caution. But too many of Mr. Trump’s pardons are not close calls; these are not remorseful people who have shown signs of reforming themselves after serving lengthy sentences, nor are these pardons necessary to restore political tranquillity [sic] (as President Gerald Ford’s pardon of Richard Nixon was widely thought to be).

The purpose of the pardon power is to show mercy for those deserving, and the reason it’s unchallengeable is because it was well understood that others would not show such mercy. This could mean to a black man in Mississippi or a cop in Minnesota. There will be hated defendants who deserve mercy, but remain so reviled that others refuse to let it be. That’s the power that will be lost once states decide to ignore the reason why the Constitution conferred the Pardon Power on the president, even though it could be used corruptly. Better to let ten miscreants go free than keep one person who deserved mercy imprisoned.