Editor's Note: This article is one of 50 in a series about Trump's first two years as president.

There is a notion of the U.S. judiciary as apolitical, as composed of—in the formulation of the current Supreme Court chief justice—impartial umpires calling balls and strikes. This is a useful, even necessary, fiction that previous presidents have seen fit to promote, even when they weren’t happy about it, in the service of preserving an independent judiciary and a functioning system of constitutional checks and balances.

Not long ago, jurists and legal scholars were scandalized when Barack Obama used his 2010 State of the Union address to reproach the Supreme Court for its decision in Citizens United, which opened the spigots of campaign finance. Not since FDR in 1937, some said, had a president so egregiously transgressed against the independence of the judiciary! But Obama’s admonishment was sufficiently mild—he didn’t accuse the justices of making an overtly political decision, or of acting in bad faith—that the only reaction from the Court itself was a slight shaking of the head and a furrowing of the brow by Samuel Alito, a display that was itself criticized as unbecomingly political for a Supreme Court justice. Chief Justice John Roberts remained silent.  

How genteel that all now seems—because the current president has been unrestrained in his criticism of judges and court decisions with whom he disagrees. And he disagrees with them a lot, as  they have repeatedly rebuked him on everything from his policy of separating families at the southern border to his Muslim travel ban to his crackdown on “sanctuary cities” to his ban on transgender people in the military. (Actually, Trump has been seeking to undermine court decisions since even before he took office, such as when he implied, in 2016, that the rulings of U.S. District Court Judge Gonzalo Curiel, presiding over a class-action lawsuit against Trump University, were illegitimate because he is “Mexican.” Curiel was born in Indiana.)  

Late last year, Trump escalated the executive branch’s clash with the judiciary to levels not often seen since the age of Marbury v. Madison, at the turn of the 19th century. In November, the administration announced a new policy requiring that migrants apply for asylum only at legal border crossings; currently, people can enter the country illegally and then seek asylum. Judge Jon Tigar, of the U.S. District Court for the Northern District of California, issued a temporary restraining order, blocking the new policy from going into effect. (The president “may not rewrite the immigration laws to impose a condition that Congress has expressly forbidden,” Tigar declared.) Talking to reporters before climbing aboard Marine One a few days before Thanksgiving, the president criticized Tigar, calling him “an Obama judge” (he was appointed by Obama in 2012), and the Ninth Circuit Court—where Northern District cases are appealed—“a disgrace.”

“Every case gets filed in the Ninth Circuit because they know that’s not law,” the president said, mangling his logic in his dudgeon. “That’s not what this country stands for. Every case that gets filed in the Ninth Circuit, we get beaten ... People should not be allowed to immediately run to this very friendly circuit and file their case.” But, the president said, “we will win [the asylum case] in the Supreme Court of the United States.”

This was too much for the normally reticent John Roberts to abide.

In an unprecedented reproach by a sitting chief justice of a sitting president, Roberts issued a statement to the Associated Press: “We do not have Obama judges or Trump judges, Bush judges or Clinton judges,” Roberts said. “What we have is an extraordinary group of dedicated judges doing their level best to do equal right to those appearing before them. The independent judiciary is something we should all be thankful for.”

Trump replied via, of course, Twitter. “Sorry Chief Justice Roberts, but you do indeed have ‘Obama judges,’ and they have a much different point of view than the people who are charged with the safety of our country.” Trump went on to deny that the Ninth Circuit represented “an ‘independent judiciary.’”

Trump is right, of course, that there are “Obama judges.” Roberts himself, like Alito, is a “Bush judge”—and the justices who elevated George W. Bush to the presidency were “Reagan judges” and “Nixon judges.” Roberts knows this. But what surely alarms him is that Trump’s politicization of the judiciary—like his politicization of the FBI and the CIA and the Justice Department and various other independent American institutions—threatens its legitimacy. (In places where the judiciary loses its independence—Hungary and Poland being two recent examples—constitutional democracy can quickly weaken and die.) In the aftermath of Brett Kavanaugh’s ascension to the highest bench—the result of a bitter, brutal confirmation process that put its own stresses on the legitimacy of the Court—Chief Justice Roberts is at pains to reaffirm the judiciary’s independence. That he felt compelled to take the unprecedented step of publicly correcting the president suggests that he believes Trump’s behavior threatens not just the authority of the Supreme Court but the viability of our political system.

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