President Donald Trump shakes hands with Supreme Court Chief Justice John Roberts after being sworn in as president on Jan. 20. Chip Somodevilla/Pool photo via AP

WASHINGTON — In an extraordinary display of conflict between the executive and judiciary branches, Supreme Court Chief Justice John Roberts rejected calls for impeaching federal judges shortly after President Donald Trump demanded the removal of a judge who ruled against his deportation plans.

“For more than two centuries, it has been established that impeachment is not an appropriate response to disagreement concerning a judicial decision,” Roberts said in a rare statement. “The normal appellate review process exists for that purpose.”

In a Tuesday morning social media post, Trump described U.S. District Judge James E. Boasberg as an unelected “troublemaker and agitator.” Boasberg recently issued an order blocking deportation flights under wartime authorities from an 18th-century law that Trump invoked to carry out his plans.

“HE DIDN’T WIN ANYTHING! I WON FOR MANY REASONS, IN AN OVERWHELMING MANDATE, BUT FIGHTING ILLEGAL IMMIGRATION MAY HAVE BEEN THE NUMBER ONE REASON FOR THIS HISTORIC VICTORY,” Trump wrote on his social media platform, Truth Social. “I’m just doing what the VOTERS wanted me to do. This judge, like many of the Crooked Judges’ I am forced to appear before, should be IMPEACHED!!!”

Trump’s post escalated his conflict with a judiciary that’s been one of the few restraints on his administration’s aggressive agenda.

He has routinely criticized judges, especially as they limit his efforts to expand presidential power and impose his sweeping agenda on the federal government. But his call for impeachment — a rare step that is usually taken only in cases of grave ethical or criminal misconduct — represents an intensifying clash between the judicial and executive branches.

The Alien Enemies Act of 1798 has been used only three times before in U.S. history, all during congressionally declared wars. Trump issued a proclamation that the law was newly in effect due to what he claimed was an invasion by the Venezuelan gang Tren de Aragua. His administration is paying El Salvador to imprison alleged members of the gang.

Boasberg, who was appointed by President Barack Obama, convened a hearing Monday to discuss what he called “possible defiance” of his order after two deportation flights continued to El Salvador, despite his verbal order that they be turned around to the U.S.

Trump administration lawyers defended their actions, saying Boasberg’s written order wasn’t explicit, while an attorney for the American Civil Liberties Union said “I think we’re getting very close” to a constitutional crisis.

The Constitution gives the House of Representatives, where Republicans hold a slim majority, the power to impeach a judge with a simple majority vote. But, like a presidential impeachment, any removal requires a vote from a two-thirds majority from the Senate.

The president’s latest social media post aligns him more with allies like billionaire Elon Musk, who has made similar demands.

“What we are seeing is an attempt by one branch of government to intimidate another branch from performing its constitutional duty. It is a direct threat to judicial independence,” Marin Levy, a Duke University School of Law professor who specializes in the federal courts, said in an email.

Only one day earlier, White House press secretary Karoline Leavitt said, “I have not heard the president talk about impeaching judges.”

Just 15 judges have been impeached in the nation’s history, according to the U.S. courts governing body, and only eight have been removed.

The last judicial impeachment was in 2010, when G. Thomas Porteous Jr. of New Orleans was impeached on charges he accepted bribes and then lied about it. He was convicted by the Senate and removed from office in December 2010.

Republican calls to impeach judges have been rising as Trump’s sweeping agenda faces pushback from the courts, and at least two members of Congress have said online they plan to introduce articles of impeachment against Boasberg. House Republicans already have filed articles of impeachment against two other judges — Amir Ali and Paul Engelmayer — over rulings they’ve made in Trump-related lawsuits.

Leavitt, meanwhile, is one of three administration officials who face a lawsuit from The Associated Press on First and Fifth Amendment grounds. The AP says the three are punishing the news agency for editorial decisions they oppose. The White House says the AP is not following an executive order to refer to the Gulf of Mexico as the “Gulf of America.”

Associated Press writer Mark Sherman contributed to this report.