For nearly a year now, a collection of lawyers challenging President Trump’s travel ban and other immigration policies have argued, with considerable success, that they are driven not by legitimate national security concerns but by bigotry.

On Thursday, Trump once again made their arguments a little easier to prove. For these litigators, the president’s vulgarities are a gift and they do indeed keep on giving.

It’s almost as if he’s throwing his own cases, albeit inadvertently.

His suggestion in an Oval Office meeting with lawmakers that the United States should stop accepting immigrants from “shithole countries” is exactly the type of statement plaintiffs’ lawyers have cited as evidence, for example, of the president’s animus toward people from the Muslim-majority countries covered in the ban.

Such statements – be they tweets, quotes from news interviews or remarks from Trump’s surrogates – have been used effectively to show unconstitutional discriminatory intent.

One federal judge after another has agreed that Trump’s own words have undermined the Justice Department’s stated defenses of his executive order, which is now in its third iteration. As one federal appeals court judge wrote in May, the travel ban “in text speaks with vague words of national security, but in context drips with religious intolerance, animus, and discrimination.”

Trump appeared to blow his top on Thursday during a private discussion with lawmakers about proposals to protect immigrants from Haiti, El Salvador and African countries. “Why are we having all these people from shithole countries come here?” he asked, according to accounts provided to The Washington Post. He went on to say that the United States should bring in more people from Norway.

Legal observers were also quick to note that Trump’s statements, which were not disputed by the White House, could become an obstacle for the administration as it tries to convince judges that the ban is constitutional.

“It might come up in the travel ban cases because the central constitutional question in those cases is, is the president motivated by animus against particular religious groups or groups defined by national origin,” Jeffrey Rosen, president and CEO of the National Constitution Center told MSNBC.

The U.S. Supreme Court has long recognized that the president has the power to exclude people from certain countries as long as he can show it’s for legitimate national security reasons. But an immigration policy targeting people on the basis of race or religion would violate the Constitution’s Equal Protection or Establishment clauses.

Just how many “shithole countries” are covered by Trump’s executive order isn’t clear. Depending on what Trump meant, it could be several. The latest version restricts travel from three African nations, Chad, Libya and Somalia. It also names North Korea, of which Trump is no fan, as well as Iran, Syria, Yemen and Venezuela. Six of those eight countries have Muslim majority populations.

“This new evidence,” Rosen said of Trump’s remarks, “distinguishing between people from some countries – African countries and those from Norway – might be invoked to suggest unconstitutional animus, and it’s possible that judges in the lower court cases could cite it.”

Indeed, it’s quite likely that legal briefs being prepared by lawyers challenging Trump’s immigration orders will now be quickly amended to include the president’s latest utterances.

“As I put the finishing touches on the travel ban brief to the Supreme Court tonight, the President’s words remind us again of how his un-American racist ideology impacts policy,” tweeted Neal Katyal, a lawyer on the travel ban case out of Hawaii.

Josh Blackman, a professor at South Texas College of Law who has defended Trump’s executive orders, suggested that a federal appeals court handling a related travel ban case may call for additional briefings “on which countries affected by the ban are ‘shithole.’ ”

We’ve been down this road before. In November, Trump threw a wrench into his administration’s effort to defend the travel ban by sharing on Twitter three inflammatory anti-Muslim videos posted by a far-right British activist. Days later, administration attorneys had to appear in the U.S. Court of Appeals for the Fourth Circuit to argue the case.

Judges seemed baffled that Trump could tweet such videos and then expect courts to rule solely on the travel ban’s official language, as Roll Call reported.

“What do we do with that?” Judge James A. Wynn Jr. asked a Justice Department attorney. “Do we just ignore reality and look at the legality to determine how to handle this case?”

Judge Pamela A. Harris also signaled that the president’s tweets clashed with the administration’s justifications for the ban, according to Roll Call. “Even with deference,” she said, “construing them in the light most favorable to the president, it’s tricky to see the national security rationale in those.”

The next round of cases expected to wind up in the courts will surely be challenges to Trump’s decision to end the temporary protected status (TPS) program that has allowed Haitians and Salvadorans to remain in the U.S. They too are certain, when the time comes, to rest their cases in part on his latest bias-laden words about their homelands.