US Supreme Court Chief Justice John Roberts has taken the extraordinary step of rebuking President Donald Trump’s criticism of a federal judge.
Mr Trump on Tuesday called a jurist who ruled against his asylum policy an “Obama judge”.
The president’s gibe has provoked a stern statement from the head of America’s highest court.
It is extremely rare for the judiciary, let alone its head, to clash with the executive branch of the US government.
“We do not have Obama judges or Trump judges, Bush judges or Clinton judges,” the chief justice told the Associated Press.
“What we have is an extraordinary group of dedicated judges doing their level best to do equal right to those appearing before them.”
Speaking on the eve of America’s Thanksgiving holiday, he said an “independent judiciary is something we should all be thankful for”.
Chief Justice Roberts – who was appointed to lead the court in 2005 by President George W Bush – was responding to the news agency’s request for reaction to Mr Trump’s remark a day earlier.
The Republican president had spoken out following US District Judge Jon Tigar’s ruling against a presidential executive order denying illegal migrants the right to seek asylum.
Chief Justice Roberts’ Supreme Court colleague Ruth Bader Ginsburg has been a far more outspoken critic of Mr Trump.
In 2016, the liberal judge apologised for calling Mr Trump a “faker” in an interview after coming under fire for commenting on a candidate as a jurist.
Mr Trump has previously lambasted federal judges for ruling against his policies. In 2017, he called a federal jurist who reversed his controversial travel ban a “so-called judge” with a “ridiculous” opinion.
Politicising an impartial judiciary
Analysis by Anthony Zurcher, BBC News
Members of the Supreme Court – in fact, the whole of the federal judiciary- like to think of themselves as above and apart from the tumult of American politics.
For some time, however, such an idea has been honoured more in the breach than the observance, with courts often becoming mired in fiercely partisan matters.
The politicisation of the judiciary is now reaching a crescendo, as Donald Trump repeatedly questions the impartiality and motives of judges.
The president is, with his comments, seemingly chipping away at the authority of a co-equal branch of government.
That may be why the president’s latest fusillade against an “Obama judge” prompted a rare and direct rebuke from the head of the judiciary, John Roberts.
The pointed statement seems destined to set off another round of criticism directed at the chief justice, who – after his 2012 ruling upholding the constitutionality of Obamacare – many Trump supporters feel is insufficiently loyal to their cause.
It is probably only a matter of time before the president, in comments or via Twitter, returns fire.
That the normally cautious jurist felt compelled to speak out underscores just how fraught the current situation has become.
This most recent feud with the judiciary relates to the large group of Central American migrants making their way to the US-Mexico border.
Mr Trump had ramped up his rhetoric around the “caravan” of migrants during the mid-term election season, calling the group “an invasion”.
He eventually deployed military troops to help secure the border.
On Tuesday, the Pentagon released a report to Congress saying this deployment of around 5,900 active-duty troops would cost about $72m (£56m), plus the $138m (£108m) already spent on 2,100 National Guard troops on border missions since April.
In addition, more than $80m (£62m) has been spent to process thousands of migrant children separated from parents under the Trump administration’s “zero tolerance” crackdown earlier this year, report US media.
Mr Trump eventually backed down on the policy that saw over 2,000 migrant children taken away from adults at the US-Mexico border between May and June.
Around 140 children remain in government custody as of this week.