• Mon. Mar 1st, 2021

Trump, who spurned legislative achievement for executive action, sees his agenda quickly undone.

As President Donald J. Trump boarded the plane home to Florida on Wednesday, he cast his administration’s policy achievements as sweeping, ambitious and, above all, enduring — but the undoing of his legacy was just about to begin.

“We’ve accomplished so much together,” he said to a crowd of his supporters. “We were not a regular administration.”

Many of Mr. Trump’s proudest accomplishments were not written in law but instead rammed through via executive fiat, making them vulnerable to reversal the moment he left office.

And that is just what happened. In his first 72 hours in office, President Biden cranked out about two dozen executive orders, using the process not to build a legacy, as Mr. Trump had attempted, but to demolish.

Mr. Trump did not master the levers of power and congressional negotiation, nor did he have much interest in the history of his office, which offered lessons on the pitfalls of relying on go-it-alone presidential power.

In a remarkable interview 10 days before his death in 1973, former President Lyndon B. Johnson explained why he had resisted the temptation to ram through landmark civil rights reforms by using executive orders. Instead, he pursued the more difficult legislative path, seeking to armor his efforts with the force of law.

Black civil rights leaders “wanted to me to issue an executive order, and proclaim this by presidential edict” said Mr. Johnson, speaking of the Fair Housing Act of 1968.

But Mr. Johnson, a skilled legislative strategist, said he did not think the reform “would be very effective if the Congress had not legislated.”

Mr. Trump did not always heed that guidance — with the exception, perhaps, of his criminal justice reform bill — and is paying the price now.

The list of Biden clawbacks is growing but so far includes: Restoring the country’s commitment to the World Health Organization, rejoining the Paris climate accords, reversing Mr. Trump’s ban on immigration from some predominantly Muslim nations, stopping construction of the border wall, reviving protections for L.G.B.T.Q. workers, killing the Keystone XL pipeline permit and re-banning drilling in the Arctic Wildlife refuge, imposing new ethics rules and tossing out Mr. Trump’s “1776” commission report.

But not all of Mr. Trump’s doings can be quickly reversed. Repealing his signature tax cuts will be a heavy legislative lift, though Mr. Biden and his aides have committed only to a partial rollback.

The packing of the federal courts with conservative judges — more a joint project between the former White House counsel Donald F. McGahn II and Senator Mitch McConnell, the Republican leader — might be Mr. Trump’s most enduring legacy. And Mr. McConnell’s use of congressional riders to repeal some regulations gave the rollbacks some force of law that may make them harder to undo.

Whether Mr. Biden will himself be overly reliant on executive action remains an open question. In fact, many of the environmental regulations put into place at the end of President Barack Obama’s term were quickly scrapped by Mr. Trump.

But Mr. Biden, a former senator who is intent on passing a massive new coronavirus relief bill quickly, seems to know the path to completing his agenda leads to legislation, including a bipartisan infrastructure package that Mr. Trump had also longed for but never championed. (For Mr. Biden, there are hopeful harbingers: a group of 17 newly-elected House Republicans signed a letter signaling their intentions to negotiate such a package.)

If Mr. Trump needed a more contemporary lesson in presidential power than Mr. Johnson’s, he had to look back no further than to his predecessor, Mr. Obama, who endured a protracted and messy process to pass his signature accomplishment, the Affordable Care Act.

That law has endured despite Mr. Trump’s repeated efforts to destroy it.