The hearts of the chattering classes have been all aflutter this week over an exchange between President Trump and Supreme Court Chief Justice John Roberts this week. The President criticized what he described as an “Obama judge” for a ruling against the administration’s attempt to bar migrants who cross the border illegally from seeking asylum. Trump has frequently commented on adverse judicial decisions, probably all his adult life and certainly since his description during the 2016 campaign of U.S. District Judge Gonzalo P. Curiel, the judge of a class-action lawsuit against the President’s now-defunct Trump University, as a “Mexican judge.”

In an apparent response Chief Justice Roberts stated, ‘‘We do not have Obama judges or Trump judges, Bush judges or Clinton judges. What we have is an extraordinary group of dedicated judges doing their level best to do equal right to those appearing before them.’’

The Chief’s second sentence is generally right but the first one is wrong. Trump responded to Roberts on Twitter, saying, ‘‘Sorry Chief Justice John 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.’’

Roberts has famously and correctly analogized a good judge as “an umpire who calls the balls and strikes.” Rule 2.00 of the Major League Baseball rule book, defines a strike zone as “that area over home plate the upper limit of which is a horizontal line at the midpoint between the top of the shoulders and the top of the uniform pants, and the lower level is a line at the hollow beneath the kneecap”  Every baseball player and knowledgeable fan knows that each umpire has his own strike zone. Like the law, it’s a matter of interpretation.

Lawyers and judges must interpret the Constitution and statutes based upon existing case law. There are indeed sharp differences on some issues between the views of most Clinton-Obama judges and most Bush-Trump judges. They do, like umpires, have different philosophical approaches to that interpretation, which tend to be influenced by their own political, and worldviews. The questions are often the extent of deference to the elected branches, supposed to represent popular will, and administrative agencies, assigned to manage matters delegated by statute. The issues affected on the national level are things like government authority, states’ rights, immigration, discrimination and voting rights. At the local level they tend to be more approaches, in criminal cases, to police procedures, rights of persons charged with crimes, pretrial detention and sentencing and, in civil cases, personal injury claims by sympathetic plaintiffs against “deep pocket” defendants.

These viewpoints are a reality. Chief Justice Roberts certainly knows there are differences in the approach of different judges to certain issues. That is, after all, why we have all these Senate confirmation fights over judicial nominees. What Roberts is actually saying is that the judges decide cases in good faith based on the law as they interpret it. For the most part I think he is right. When the law is not clear that can produce different results from judges with different understandings. The Supreme Court is there to resolve those differences. The number of split decisions from the Supreme Court itself evidences that these are legitimate differences.

Trump is hardly the first President to complain about judicial decisions. What makes his comments seem unprecedented are their harsh edge, heightened by the limits on the forum of Tweeter.

Such outspoken animus goes back to the harsh inter-branch relations between President Thomas Jefferson and Chief Justice John Marshall. The long-serving Marshall was still around to spar with President Andrew Jackson, inspiring the probably apocryphal Presidential rejoinder, “John Marshall has made his law. Now let him enforce it.”

The revered President Franklin D. Roosevelt complained bitterly about the conservative Supreme Court striking down his New Deal measures during the Depression. At the peak of his power, just after the record-setting reelection in 1936 in which he carried 46 of the 48 states and retained overwhelming majorities in both Houses of Congress, Roosevelt attempted to “pack” the Court by legislation increasing its size, allowing him some appointments to change the balance. Characteristically devious, FDR couched his proposal in terms of “helping” elderly judges keep up with the workload, by having the Court temporarily enlarged by one judge for every sitting judge over the age of 70. It was all too much for the nation to swallow. The measure failed and FDR’s domestic power was never the same again.

In 1968 Richard Nixon was elected in good part on his promise to appoint “law and order” judges in reaction to a perceived increase in crime and disorder following the Warren Court’s revolutionary decisions, expanding the ability of criminal defendants to have evidence from searches and confessions excluded from their trials.

It is well known among lawyers that the 9^thCircuit Court of Appeals, by the accident of the timing of the appointments of its members is exceptionally liberal. Only by that fluke, has it seemed on occasion since the 2016 election that the 9^thhas joined The Resistance. What is unusual about the President’s comments is, as I have said, not their substance but their tone.

The Chief Justice’s reply to Presidential comments is unusual but it has been done. Chief Justice Charles Evans Hughes replied to FDR’s Court-Packing plan with statistics plainly demonstrating that the justices were quite productive. He told Congress that the oldest Justices turned out the most opinions and that the Justices required no “help” to keep up with their workload.

Chief Justice Roberts is properly very protective of independence of the courts and his remarks seem to be directed more to showing his judges, who are generally not allowed to comment on such things, that he is looking out for them.