Like so many others, I was saddened to learn of the passing of Justice John Paul Stevens. He was a fellow Midwesterner, honest, self-effacing and kind, but with a strong independent streak and a passion for justice. I had the privilege of interviewing with him for a clerkship once, and then observing him up close for a year as I clerked for Chief Justice William Rehnquist. He was the quintessential gentleman and scholar.

But commendable personal qualities do not always translate into judicial virtues, particularly when it comes to the objective and consistent application of established rules of law. Justice Stevens was admirably candid about the fact that his judicial philosophy was heavily informed by his personal experiences and what they had to teach him. In his view, sound decision making was about applying reasoned judgment to the particular facts of a case. He was no doubt sincere in his desire to achieve a just result every time.

You might think that a strong sense of justice is a desirable judicial quality. But such senses are usually based on value judgments derived from personal experiences and preferences, or what we sometimes call political ideology, rather than the rule of law. What one judge believes justice requires can differ radically from the beliefs of other judges. All of a sudden, we have gone from the rule of law to the rule of individuals.

Among Justice Stevens’s liberal admirers, his flexible approach to the law has been cause for celebration: He was the moderate Republican appointed by President Gerald Ford who evolved into the enlightened liberal leader of an increasingly conservative Supreme Court. But whatever your political leaning, this narrative should be troubling, for it defines Justice Stevens’s career by reference to a shifting political ideology, not a commitment to a consistent, impartial approach to adjudication.