In an email to colleagues on Sunday, Brad Karp explained his decision to make significant concessions to the White House in the face of an executive order that targeted his firm, Paul, Weiss, Rifkind, Garrison & Wharton.
The order, the latest in a series of similar actions targeting law firms whose lawyers have performed legal work that Trump dislikes, threatened the suspension of security clearances for Paul Weiss lawyers as well as the termination of any federal contracts involving the firm.
It noted that a former Paul Weiss lawyer, Mark Pomerantz, had been a central player in an investigation by the Manhattan district attorney's office into Trump's finances before he became president.
On Thursday evening Trump announced he had rescinded the order following a White House meeting with Karp.
The White House said the firm had agreed to dedicate $US40 million ($A64 million) worth of free legal services to support the Trump administration agenda, including on countering anti-Semitism; not pursuing diversity, equity and inclusion considerations when hiring and to taking on clients regardless of political affiliation.
The resolution triggered an intense backlash within the legal community, with lawyers criticising the firm for capitulating to Trump, particularly at a time when he's using the power of the presidency to threaten the livelihoods of lawyers and companies he believes have crossed him.
The deal also reflected Trump's recent success in extracting concessions from a broad swathe of targets, in both academia and private industry, who have opted to compromise rather than fight.
In an email to Paul Weiss employees obtained by The Associated Press, Karp described the order as having presented an "existential crisis" for the firm.
He said it was very likely the firm would not have survived a protracted fight with the Trump administration.
"The executive order could easily have destroyed our firm," Karp wrote.
"It brought the full weight of the government down on our firm, our people, and our clients.
"It threatened our clients with the loss of their government contracts, and the loss of access to the government, if they continued to use the firm as their lawyers," he wrote.
"It raised the spectre that the government would not hire our employees."
The firm was initially prepared to challenge the executive order in court until "it became clear that, even if we were successful in initially enjoining the executive order in litigation, it would not solve the fundamental problem, which was that clients perceived our firm as being persona non grata with the Administration".
The firm is one of numerous Trump targets that have recently reached agreements with the administration rather than provoke the president's ire.
Columbia University agreed to put its Middle East studies department under new supervision and overhaul its rules for protests and student discipline, acquiescing to an ultimatum by the Trump administration to implement those changes or risk losing billions of dollars in federal funding.
Meta and ABC made settlement payments to Trump's future presidential library to end lawsuits filed by Trump.
