Healthy debate, even coarse discourse, can be a sign of a vigorous, free and open society. Yet in demeaning and challenging a co-equal branch of government, President Trump dangerously ignores a foundational principle of our Republic.

During this recent litigation, Trump referred to the Federal District Court judge in Seattle as a “so-called judge” after the court temporarily suspended the administration’s ban on travelers from seven predominately Muslim countries. Once the case moved to the 9th Circuit Court of Appeals, the president, unhappy with the oral argument, suggested that the court seemed to be “so political” and he offered his opinion that “even a bad high school student” would rule in his favor.

When asked, Supreme Court nominee Judge Neil Gorsuch characterized Trump’s verbal assaults on these federal judges as “disheartening” and “demoralizing.” He further stated, “Any attack on brothers or sisters of the robe is an attack on all judges.”

Judge Gorsuch spoke truth to power.

Judges need to have thick skins and should expect criticism of unpopular decisions, even though we’re constrained by judicial ethics from responding to such criticism. Public comment on decisions is a hallmark of a free society.

However, personal attacks against a judge fall into a different category. Lawyers who recklessly and falsely make personal accusations against judges are subject to professional discipline, even risking suspension. That’s because lawyers are officers of the court with a special responsibility to support public confidence in the judicial process. Non-lawyer members of the public, even government office holders, are under no similar restraints.

In my view, and regardless of the potential source of a personal attack against a judge, the durability of our form of democracy depends on the ability of a judge to render judgments free from political or populist opinion. This means that even non-lawyers, unbound by professional restraints, would be wise, in the name of good citizenship, to temper personal assaults on judges.

To wrestle with the tension between judicial independence and public criticism of the judiciary, we should consider two notions that form the bedrock of any civilized society — judicial independence and the rule of law. Former Supreme Court Justice Felix Frankfurter once famously said: “There can be no free society without law administered through an independent judiciary. If one man can be allowed to determine for himself what is law, every man can. That means first chaos, then tyranny.”

In short, judicial independence is a foundational principle, but its value is tied to the notion that a judge is bounded only to the law in decision making. The faithful discharge of the judicial duty requires fidelity to the Constitution, to legislative enactments, and to judicial precedent.

In issuing a decision, a judge owes no obligation to public opinion. To the contrary, judicial courage is often displayed by an unpopular decision that does not reflect the judge’s personal preferences but which the judge believes is mandated by the faithful application of the law. In that delicate arena, where rights and obligations are in the balance, there is no place for political or populist influence or pressure.

The second great notion is captured in the term “rule of law” and reflected in the saying that we have a “government of law, not men”. The concept of the rule of law dates back to England in 1215 and the Magna Carta, which was signed by King John at the insistence of powerful noblemen who recognized the inalienability of the individual rights of free men.

The framers of our U.S. Constitution are Magna Carta’s heirs. When our founders formed our government to be composed of three branches of government, they gave each sector its sphere of operation while the Constitution provided, through the Bill of Rights, for the protection of individual liberties. This form of government, for the first time in world history, included an independent judiciary, co-equal with the legislative and executive branches, each operating in an orbit of independence and codependence.

We succeed as a government only if each branch faithfully fulfills its responsibility while acknowledging the separate authority of each sister branch. James Madison, one of the two primary framers, and co-author of the Federalist Papers and later president, stated: “If men were angels no government would be necessary. In framing a government which is to be administered by men over men the great difficulty lies in this: you must first enable the government to control the governed; and in the next place oblige it to control itself.”

Madison’s sage words deserve primacy in today’s discourse.

Judge Thomas A. Bishop is a retired member of the Connecticut Appellate Court where he continues to hear appeals on a part-time basis. He is also a former adjunct professor of law at the University of Connecticut Law School, where he taught a seminar on judicial independence.