WASHINGTON — For someone trying to demonstrate that the judiciary is not political, getting into a political fight with the president sure is a funny way to do it.

After President Trump called a judge who ruled against him an “Obama judge,” Chief Justice John Roberts issued an extraordinary public rebuke of the president, declaring in statement “We do not have Obama judges or Trump judges, Bush judges or Clinton judges.” Roberts was not only wrong to speak out, but also his claim that there are no Obama judges or Trump judges was wrong.

If we do not have Obama judges or Trump judges, then why did Senate Republicans block President Barack Obama’s nomination of Merrick Garland to replace the late Justice Antonin Scalia in the final year of Obama’s term? And why did Democrats filibuster Trump’s nominee, Neil Gorsuch, to fill Scalia’s seat?

Even Roberts’s fellow justices know there is a difference. If there were no Obama judges or Trump judges, then why did Anthony Kennedy wait for Trump’s election to announce his retirement? And why doesn’t Justice Ruth Bader Ginsburg just retire now and let Trump nominate her replacement? Because they both want a president who would appoint a successor who shares their judicial philosophy. (And, lo and behold, Trump appointed a former Kennedy clerk, Brett Kavanaugh, to succeed him).

The American people know that Roberts is wrong. In the 2016 election, exit polls showed that 70 percent of voters said Supreme Court appointments were either the most important or an important factor in deciding their vote. And polls show that Republicans expanded their Senate majority in 2018 in large part because conservative voters were angered over the left’s brutal campaign of character assassination against Kavanaugh.

Roberts is correct that we should not have “Trump judges” or “Obama judges.” It would be better for the country if every judge, regardless of which president nominated him or her, strictly interpreted our laws and the Constitution. But the reality is that not all do. While conservative presidents tend to nominate judges who exercise a philosophy of judicial restraint — follow our laws as written — liberal presidents tend to nominate judicial activists who legislate from the bench and shape the law to reach their preferred outcomes. The left believes in a “living Constitution,” which can be interpreted to mean whatever they want it to mean without being formally amended.

Democratic presidents have been much more successful than Republicans in nominating judges who hew to their judicial philosophy. Over the past three decades, nearly half of all Republican Supreme Court nominees have either become “swing votes” (Sandra Day O'Connor, Kennedy) or defected to the court’s liberal bloc entirely (David Souter). Even Roberts has joined the court’s liberal bloc at key times, abandoning his judicial philosophy that judges should not legislate from the bench to provide the swing vote to uphold Obamacare. By contrast, not one liberal justice during the past three decades has defected to the conservative bloc or turned into a regular swing vote.

What is true of the Supreme Court applies even more to the appellate courts. Trump is right, the U.S. Court of Appeals for the 9th Circuit is a disgrace. This is the court that ruled that the phrase “under God” in the Pledge of Allegiance was unconstitutional, that the Second Amendment doesn’t recognize an individual right to bear concealed arms and that bans on assisted suicide are unconstitutional.

This is why it is so important that Trump has nominated, and the Senate has confirmed, a record number of district and circuit court judges — and why liberals are aghast at the pace of Trump’s judicial confirmations. As former Hillary Clinton adviser Ronald Klain complained, “Trump’s judicial nominees will be deciding the scope of our civil liberties and the shape of civil rights laws in the year 2050 — and beyond.” Everyone, left and right, knows that Roberts is wrong.

We do have an independent judiciary. Judges are not beholden to any president, including the one who appoints them. The judiciary plays a key role in our system of checks and balances. “Trump judges” should rule against Trump when he is wrong. That is why it is so important for the chief justice stay above politics. Roberts is right that our “independent judiciary is something we should all be thankful for.” Rolling around in the rhetorical mud with Trump is not just bad form; it also undermines the very judicial independence Roberts is seeking to uphold.

© 2018, The Washington Post Writers Group