Rule of law has long been sacred to the classical liberal.  While the term was popularized by British jurist A. V. Dicey, the concept is much older.  The rule of law has three distinct characteristics in the common law world:* 

  1. An absence of arbitrary power on the part of the government
  2. Every man (regardless of rank or condition) is subject to ordinary law administered by ordinary tribunals
  3. The law is discovered by judges when considering cases brought before the courts

This last is often a cause for controversy.  Why should judges decide law?  If judges simply decide, and those decisions become legal precedents, aren’t judges just substituting their judgement for politicians?  Why do judges deserve special reverence when classical liberals are skeptical of politicians?  Or, as it’s sometimes put, aren’t judges just “politicians in black robes?”

These are legitimate questions.  Fortunately for us, public choice analysis lets us explore them.  The reality is that judges are not special people.  Just like any other person, they face incentives and those incentives influence their behavior.

In their 2006 book Judge and Jury: American Tort Law on Trial, Claremont McKenna College economist Eric Helland and George Mason University economist Alex Tabarrok explore how incentives faced by judges, juries, and other officers of the court affect judicial outcomes.  One of their big findings is that tort awards are often driven by political factors such as judicial elections.  In other words, when judges face elections for their seats, they tend to award higher claims to plaintiffs than those who are appointed for life.  When judges are treated as politicians, they tend to act as politicians in black robes.  When judges are treated as arbiters of the law, they tend to act as arbiters of the law.

While judicial procedures differ at the state level, federal judges are appointed.  In the media, the president who appointed a judge is often mentioned (e.g., “‘That is unconstitutional retaliation and viewpoint discrimination, plain and simple,’ wrote the judge, an appointee of former President Barack Obama. Or “Rodriguez, who was nominated to the bench by Trump during his first term, ruled the government can’t detain the plaintiffs solely on the basis of the Alien Enemies Act.”).  Commentary on Supreme Court decisions often talks about the ideologies of the justices when discussing how they voted.  Fascinatingly enough, the ideologies do not seem to matter much.  American federal court rulings are amazingly consistent.  When judges are appointed for life (or good behavior), they tend to rule consistently.  Conversely, when they are elected, judges tend to rule less consistently and play to the electorate.

And there are other incentives at play as well: appeals courts/the Supreme Court can overturn decisions of lower judges (and judges do not like having opinions overturned), in extreme cases, judges can be impeached, etc.  In other words, the incentives are for judges to be consistent, not political.  

Of course, there are times when ideology might matter.  For Supreme Court decisions, ideology might play a larger role than in lower courts’ decisions.  But this potential outcome is due to the nature of the cases that make their way to the Supreme Court.  The Supreme Court deals with cases where there is no clear law—where legitimate differences of interpretation can exist.  The Supreme Court doesn’t deal with every case, but rather with unclear cases.  Since these cases are unclear, ideology may be a factor that ultimately shapes the opinion.  And that even depends on the justices.  Chief Justice Roberts puts emphasis on strong consensus, and his courts have churned out an incredible number of unanimous decisions.  In the 2022 term, for example, nearly half (48%) of the Court’s decisions were unanimous.

So, classical liberals like myself put a lot of faith in the courts because of the incentives they face.  If those incentives were different, then our opinions of judges would be different.  Now, this is not to say that the Courts will always get the decision right.  The US alone has numerous decisions where the Courts obviously got it wrong: Dred Scott v Sandford, Plessy v Ferguson, Korematsu v United States, Wickard v Filburn, etc.  Some have been overturned (Dredd Scott by Constitutional amendment, Plessy by Brown v Board) whereas others remain precedents, either enforced (Wickard) or ignored (Korematsu). 

Incentives are not mind control, and there will be times when ideology influences decisions.  But in general, the incentives faced by judges and justices are different than those faced by politicians, so it is unfair to consider them just politicians in black robes.

For more reading, I recommend Federalist 78, where Alexander Hamilton makes similar arguments as I do here.  In a similar vein, GMU law professor Todd Zywicki has an interesting paper on how the doctrine of stare decisis can transform the incentives of litigants and judges (see, in particular, Section III.A).

*For a classic treatment, see AV Dicey’s Law of the Constitution, Chapter IV.  Bruno Leoni’s Freedom and the Law is another excellent read.  For the history of the development of Common Law, I recommend Maitland & Pollock’s History of English Law Before the Time of Edward I and Plucknett’s A Concise History of the Common Law.