The Donald Trump administration is officially gone, but some of the deeper wounds it left in our republic remain — as do lessons on how to better fortify our political institutions against a similarly reckless executive.

On his way out of the Oval Office, Mr. Trump unleashed a flurry of 11th-hour pardons and clemencies. They were doled out on the same basis as most of his other pardon power flexes over the last four years: a get-out-of-jail free card for his cronies and other like-minded corruption fiends. If anything can be wrung out of Mr. Trump’s final insult to the dignity of the presidential office, it should be a serious effort at pardon reform to ensure the power is not so easily abused.

As a pandemic kills thousands a day, the people that received Mr. Trump’s last moments of presidential attention were a veritable potpourri of serpentine self-dealers and political hacks. Randy Cunningham and Robin Hayes, former congressmen convicted in separate bribe schemes stemming from their time in office, were each granted clemency. William T. Walters, a sports gambler convicted in an insider-trading scheme who is a client of Mr. Trump’s former lawyer John Dowd, had his sentence commuted. Ken Kurson, a friend of Jared Kushner and associate of Rudy Giuliani, was charged with cyberstalking and harassment during his divorce; Elliot Broidy, a Trump campaign fundraiser, took $9 million from a Malaysian fugitive financier to push for favors from the administration — both received pardons.

Amid the plethora of end-runs on justice Mr. Trump squeezed through during his last day behind the Resolute desk, perhaps the most egregious is Steve Bannon. A former right-wing media mogul turned presidential adviser, Mr. Bannon was indicted last year in a scheme involving hundreds of thousands of Americans who contributed to a crowdfunding effort to privately finance a U.S.-Mexico border wall. According to court documents, Mr. Bannon and his collaborators conspired to cheat the donors by falsely promising that their money had been set aside while skimming funds for personal use — a plot he was caught on video joking about.

Mr. Bannon’s pardon is uniquely perverse. It puts an exclamation point on how closely Mr. Trump’s transactional behavior as president resembled a mob boss more than a commander in chief, shielding Mr. Bannon form justice seemingly as a reward for the loyalty of not testifying against Mr. Trump in the Russia and impeachment investigations. As a result, the message resounding from the highest office in the land is loud and clear: Grift all you want free of consequence, so long as you’re well-connected. Furthermore, the pardon precludes a trial for Mr. Bannon. This means the truth — that the architects of the so-called “Make American Great Again” movement are not so preoccupied with patriotism but with fleecing their most ardent supporters — will never get its day in court. The countless Americans bilked to the tune of $25 million by Mr. Bannon and his co-conspirators will never have the wool pulled from their eyes, thanks to Mr. Trump’s final abuse of presidential power — a fitting capstone to a presidential legacy of obfuscation and mendacity over transparency and service to those who elected him.

The presidential pardon power is enshrined in Article II of the Constitution, and as such there isn’t much room for limiting its use. Mr. Trump has shown the damage that can be done to justice when the person wielding that power does so with a deep disdain for accountability. The legislative branch should respond by seeking ways to make this executive power more accountable, even if it can’t be directly limited. A new law could require a president to inform Congress in writing and give reason for any pardons, clemencies or commutations in the last 100 days of a presidential term. The law could also require that any related Justice Department files be turned over to a relevant congressional committee for appropriate analysis and airing out. This would at least bring some basic sense of oversight and clarity in instances like Wednesday, where Mr. Trump pushed through nearly 150 pardons and clemencies in a single day on his way out the door.

The pardon power has been interpreted as an “escape valve” of sorts for situations when justice meted out at a certain time in the past no longer seems just. Mr. Trump’s actions have thoroughly underscored the extent to which this power can be nakedly abused.

Healing from the era of Trumpism will entail identifying the tension points in our democratic institutions that are ripe for exploitation to the detriment of our Constitution and our nation. Part of this repair includes rethinking the contours of executive power; presidential pardon reform would be a good start. The real cure is recognizing the danger of demagogues with authoritarian tendencies before they are given that power.