A scholar of political institutions says how Trump’s pardon deviates from other presidential pardons.

It is hard to gauge the political fallout of the president’s decision — announced as it was late on a Friday night during an impending hurricane. Normally, though, as political scientist Jeffrey Crouch’s book on the pardon power makes clear, pardons are granted for two reasons: either to provide mercy or correct a miscarriage of justice, in an individual case; or on more general grounds based on public policy.

Trump’s doesn’t fit the mercy category very well, because of its haste and because of the lack of contrition.

(Further, in considering such petitions, “The extent to which a petitioner has accepted responsibility for his or her criminal conduct and made restitution to its victims are important considerations.”)

Yeah that’s not Arpaio. He’d do it again if he could.

Pardons also serve as a check against the judicial branch, when the president feels a grave miscarriage of justice has occurred. At his Phoenix rally, Trump seemed to make this claim, saying that “Sheriff Joe was convicted for doing his job.”

The problem with that, though, is that Arpaio was convicted for doing the opposite of his job. As a sworn officer of law enforcement, he violated the law and then ignored court orders designed to bring his policies in line with statutory and constitutional mandates.

This is an important point. His job is to enforce the law, and he himself flipped the bird at the law.

Two different federal judges found, respectively, that the “constitutional violations” committed by Arpaio’s office were “broad in scope, involve its highest ranking command staff, and flow into its management of internal affairs investigations” and that he “willfully violated” directives to correct those violations.

That in turn circles back to the public policy rationale for pardons. Presidents have given clemency to both individuals and groups, arguing that doing so serves the broader public good — such cases range from Thomas Jefferson’s 1801 pardons of those convicted under the Alien and Sedition Acts to Gerald Ford’s 1974 pardon of former president Richard M. Nixon to Barack Obama’s commutation of more than 1,700 prison terms he thought were skewed by the past mandatory imposition of long sentences even for nonviolent crimes.

Here, though, it is hard to see how the public interest has been served. Rather than “restore the tranquility of the commonwealth” (as Hamilton thought a pardon might do), Trump’s action seems likely to harden its divisions. Arpaio’s status as what George W. Bush speechwriter David Frum calls “America’s second most famous Obama birther” and his long history of abusing his office hardly makes him a symbol of the unity the president has intermittently claimed to desire after Charlottesville. And pardoning a sheriff for disobeying federal law is substantively out of step with the constitutional mandate that the president faithfully execute that law — and with the foundational American concept of “a government of laws and not of men.”

In other words it’s disastrous in pretty much any way you can look at it.