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 provoked a stern statement from the head of America’s highest court.
Mr Trump has defended his comments, saying Chief Justice Roberts is wrong.
It is the first time the chief justice has spoken against Mr Trump.
“We do not have Obama judges or Trump judges, Bush judges or Clinton judges,” Chief Justice Roberts told the Associated Press.
Mr Trump responded on Twitter on Wednesday, saying the top justice was wrong and that “Obama judges… have a much different point of view than the people who are charged with the safety of our country”.
He suggested that the 9th Circuit Court, where a federal judge blocked his recent immigration proclamation, opposed his policies on border and safety.
Why did Chief Justice Roberts speak out?
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, calling the 9th Circuit “a disgrace”.
“I’m going to put in a major complaint because you cannot win – if you’re us – a case in the 9th Circuit and I think it’s a disgrace,” Mr Trump told reporters outside the White House.
“This was an Obama judge. And I’ll tell you what, it’s not going to happen like this anymore.”
Politicising an impartial judiciary
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.
The president was very quick, via Twitter, to call recent lower-court decisions suspending his immigration policies “dangerous and unwise”.
That the normally cautious jurist felt compelled to speak out underscores just how fraught the current situation has become.
About 3,000 members of the caravan have so far arrived in Tijuana, the Mexican city bordering the US, and authorities expect numbers to reach 10,000 in coming weeks.
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.