Opinion | Accountability After Trump

There are also powerful arguments against an administration investigating and prosecuting its opponent. No matter how strong the evidence or how independent Mr. Biden’s attorney general, it will inevitably look to half the country like a political hit job. Perhaps that shouldn’t matter, but from a practical standpoint it’s hard to convince Americans that the Justice Department is not politicized when it’s prosecuting the preceding administration.

Then there’s the issue of triage. The moment Mr. Biden takes office he will be saddled with a staggering pileup of emergencies demanding his immediate attention: a pandemic killing thousands of Americans daily; a crippled economy, mass unemployment and miles-long food lines; a worsening climate crisis; and the growing threat of right-wing terrorism and racist violence. Then there was this week’s revelation that the Russian government is behind a huge, monthslong cyberattack on dozens of federal agencies and companies, posing what officials called a “grave risk” to the federal government.

Despite the challenges, the nation has to move forward.

Many of the most needed reforms fall into the same category as those that were adopted in the aftermath of Watergate: reducing the power of the presidency and re-empowering institutions, like Congress, that are supposed to serve as checks on an imperious executive. Those reforms managed to hold the line for a while, but they turned out to be ineffective at reining in a president with Mr. Trump’s sheer tenacity and disregard for the rule of law. While Mr. Trump failed to fully exploit their weaknesses, a more devious and competent demagogue would be much more likely to succeed.

Corruption and abuse of power are the most urgent issues in need of addressing.

Four years into Mr. Trump’s presidency and nearly five years since he promised to release his full tax returns, the American people still don’t know how much his personal financial interests and entanglements are intertwined with his administration’s domestic- and foreign-policy decisions. He has an affection for strongmen, but is his solicitousness toward leaders like Russia’s Vladimir Putin, Turkey’s Recep Tayyip Erdogan and Saudi Arabia’s Mohammed bin Salman a result of something more mercenary? New laws compelling all presidential candidates to release at least 10 years of their tax returns, as well as a comprehensive list of any possible conflicts of interest, financial and otherwise, should be an obvious step toward reform. Legislation should also bar presidents from being involved in overseeing any business while serving in office.

These reforms would need to apply throughout the executive branch. As the nation has seen, Mr. Trump’s administration has been awash from the start in self-dealing, ethical investigations and scandals. From cabinet secretaries to agency heads, the list is long, and likely incomplete.

The second major area for reform involves presidential abuse of power, which includes everything from violations of the Hatch Act to the destruction of presidential records. The larger concern is the politicization of law enforcement. Mr. Trump was open in his belief that the Justice Department should do his bidding. He pressured his attorneys general, from Jeff Sessions through William Barr, to protect him and his allies and prosecute his perceived enemies. Sometimes they consented. Other times they resisted. But if law enforcement is to operate fairly and effectively, the American people have to see it as independent from politics.

Mr. Trump has also abused his power by pardoning friends and associates who have been convicted of serious crimes. More recently he has floated granting pre-emptive pardons to family members and even himself, which may be unconstitutional. Mr. Trump isn’t the first to test the pardon power’s limits, but he has politicized and personalized it to an unparalleled degree. Since the power is essentially absolute, any meaningful change to it would require a constitutional amendment.