The law firm Jenner & Block sued the Trump administration on Friday, seeking to stop an executive order that could cripple the firm’s ability to represent clients.
The lawsuit is the second time that a big law firm targeted by President Trump has decided to fight back in court and will open a new front in the month-old battle Mr. Trump has waged on such firms. The president’s orders against white-shoe law firms he perceives as enemies have stripped lawyers of security clearances, barred them from entering federal buildings and discouraged federal officials from interacting with firms.
“Today, Jenner & Block filed a lawsuit to stop an unconstitutional executive order that has already been declared unlawful by a federal court. We expect to prevail quickly,” the law firm said in a statement.
The firm created a website — Jenner Stands Firm — to publicize its filing and to highlight newspaper editorials criticizing the executive orders and comments from law school professors questioning the legality of Mr. Trump’s actions.
Last week, Mr. Trump and the law firm Paul Weiss announced an agreement in which Mr. Trump rescinded his executive order against the firm in exchange for it committing to represent clients regardless of their political leanings and pledging $40 million in pro bono legal services to issues Mr. Trump has championed.
That deal was widely criticized, as the firm — which is stocked with Democrats who have opposed Mr. Trump — was seen as bending to the president to protect its bottom line. Another big law firm, Skadden Arps, is in talks with the White House to head off a potential executive order aimed at it.
Mr. Trump has been going after big law firms that he contends have “weaponized” the legal system. He is initially targeting law firms that hired lawyers who were once involved in the many investigations of his actions during his first presidential term and his business dealings.
The executive orders have been premised on the notion that the law firms’ alleged partisan representations and pro bono work for groups that Mr. Trump disagrees with could pose a threat to national security.
The suit by Jenner & Block was filed in federal court in Washington and the firm is asking a judge to step in immediately and stop the executive order, which was leveled against it by Mr. Trump this week. The firm is being represented by Cooley, another law firm. The lawsuit named numerous government agencies and officials as defendants.
The executive order accused the firm of engaging “in obvious partisan representations to achieve political ends” and claimed the firm “discriminates against its employees based on race and other categories prohibited by civil rights laws, including through the use of race-based ‘targets.’”
On Thursday, Mr. Trump issued a similar executive order against Wilmer Hale, the law firm where Mr. Mueller, a former F.B.I. director, had worked.
Jenner & Block’s complaint said that Mr. Trump’s action was unconstitutional and would compromise the ability of the firm’s more than 500 lawyers to “zealously advocate for its clients.”
The lawsuit noted that Mr. Trump’s deal with Paul Weiss did not include any new security measures imposed on that firm.
Perkins Coie, one of the first law firms targeted by Mr. Trump, filed a suit against Mr. Trump earlier this month. A federal judge temporarily halted Mr. Trump’s order, saying that it was likely illegal and adding: “It sends little chills down my spine.”
Jenner & Block is seeking to have that same judge — Beryl A. Howell — handle its suit.
Vanita Gupta, a civil rights lawyer and former senior Justice Department official in the Biden and Obama administrations, said the new lawsuit was necessary in a time of peril for the legal profession.
“The only way through this attack on the very foundations of our legal system is by fighting back,” Ms. Gupta said. “If firms want to be trusted to fight the biggest fights, they must not cave to blatantly unconstitutional government actions.”
A White House representative said Mr. Trump had targeted Jenner & Block because it once employed Andrew Weissmann, a longtime federal prosecutor who worked under Robert S. Mueller III, who as a special counsel investigated ties between Mr. Trump’s campaign and Russia.
Mr. Weissmann has a reputation as an aggressive investigator. In recent years, he has emerged as a public critic of Mr. Trump, appearing frequently on MSNBC to provide legal analysis about the range of indictments Mr. Trump faced for his conduct.
In the complaint, the firm said that Mr. Weissman had not worked for it since 2021. It also noted that it has had prominent lawyers from all political parties on its staff.