Law Professors: Three Centuries of Shaping American Law. By Stephen B. Presser. West Academic Publishing; 486 pages; $48.

CONTROVERSY is raging over Donald Trump’s decision to appoint Neil Gorsuch to the Supreme Court. Within hours, accusations were being made about the candidate’s political affiliations, about whether he is in the legal mainstream and whether he could protect the “enshrined rights of all Americans”.

The idea of “rights”, “mainstream” and even the role of the Supreme Court in determining these are not as enshrined as advocates of various positions contend. They never have been. Many ideas abound about the role of the court within America’s political system, the principles it should uphold and even the definition of a ubiquitous term, “rule of law”. Some of these debates trace their roots back to the early 18th century, before America was even established.

If the fight has become more heated, it is because the authority of the judiciary in America, notably its ability “to legislate”—to expand the reach of law and find new, unstated (and possibly unintended) rights—has been a pivotal feature of politics since the 1950s. “Law Professors: Three Centuries of Shaping American Law”, a well-timed book by Stephen Presser, a professor at Northwestern University, traces how this emerged.

The book is organised around the intellectual biographies of 29 individuals, including one Barack Obama, who spent 12 years as a senior lecturer at the University of Chicago before taking an eight-year tour as America’s president. “There is no country on Earth in which law professors have played a more prominent role,” writes Mr Presser, a statement that neither lawyers nor politicians in any camp would dispute.

The natural audience for this book is academics, members of the bar and law students. For these last in particular, it may become essential reading. Law professors like putting their students through the hoops by asking them bewildering questions; Mr Presser’s book does a good job of distilling what is actually being taught. Given the timing of the book, though, its greatest value may lie in the way it explains why potential candidates are so often described, by different interested parties, as being ignorant, bigots or temperamentally unsuited to the task at hand.

“Our two major political parties now understand the rule of law very differently,” Mr Presser writes. Should it be based on precedent and written statutes (basically the Republican approach) or should it be discretionary and allowed to incorporate values and external information (the Democrats’ view). Within this schism is a struggle over whether the judiciary’s role is to enforce laws as they were written or to see law as a flexible instrument to achieve objectives, many of which are passionately supported—and passionately opposed.

That law professors became pivotal players in this drama was never inevitable. As in Britain, in America’s earliest days legal training came through apprenticeships. This was augmented by a few intellectually ambitious outside authorities who found their way to universities. One of the earliest law professors, Joseph Story, simultaneously taught at Harvard, served as a justice on the Supreme Court, wrote treatises instructing judges and lawyers on the law and ran a bank (which may have been perceived at the time as an added benefit rather than a conflict of interest).

In his spare time, Story hosted Alexis de Tocqueville during his trip to America, and is thought to have been a key influence in de Tocqueville’s assertion that lawyers served as America’s aristocracy, and “constitute a sort of privileged body in the scale of intellect”, who serve as “the most powerful existing security against the excesses of democracy”. These lines are often repeated—less so a subsequent passage, noting that beyond their virtues, they, “like most other men, are governed by their private interests, and especially by the interests of the moment”.

These three sentiments: that the study of the law is the preserve of lawyers, who are the intellectual elite; that they serve as a deterrent against the failures of democracy; and that they may be compromised, if not flawed, in their approach, are dominant themes throughout Mr Presser’s book. In practice, Story was one of many prominent Americans who tried to distil law from cases that were largely but not exclusively British, reflecting differences such as lack of a monarchy. Although this was a formidable task, it was limited to determining what were, in fact, the rules of law.

The pedagogical approach was formalised in the late 19th century by Christopher Columbus Langdell, a dean of Harvard Law School, who developed what became the practice of deciphering a vast number of appellate decisions to understand what were perceived to be scientific principles and logic. But even as this approach to legal training became common, intellectually the fact that the law could be discerned through its history was never entirely satisfactory to its most ambitious practitioners. In response to a casebook on contracts compiled by Langdell, Oliver Wendell Holmes, yet another professor at Harvard Law School and a Supreme Court justice, wrote, “The Life of the Law is not logic, but experience.” Even if the same rules were invoked, over time they served different purposes, in Holmes’s view.

It is this premise of a flexible law that became the animating force in law schools and ultimately in American courts and policy, largely through a series of movements that Mr Presser describes with as much precision as this somewhat murky procession allows. Among the most important was “legal realism”, which, as Holmes’s statement suggests, examined what judges actually did, rather than the rules of law¸ and encouraged them to incorporate research from social sciences in making their decisions. This was adopted by the Supreme Court under Earl Warren after the second world war and played a huge factor in many of its most notable decisions, including Brown v Board of Education in 1954, which concluded that segregation was unconstitutional, not because of segregation itself but rather because of testimony drawn from research about the psychological harm that segregation imposed.

The notion of the court as a mechanism for going beyond statutes and past decisions to define justice opened up a wide field of study in the latter half of the 20th century. Among the many professors to shape the judicial system during that time were Ronald Dworkin, a professor at New York University and Oxford, who argued that law must be debated on the basis of moral concepts rather than rules; Richard Posner, a senior lecturer at the University of Chicago and a federal judge, who has been called the single most cited legal authority largely because of his development of cost-benefit analysis; and, conversely, Cass Sunstein, also of Chicago, then Harvard, then the Obama administration, who concluded that the failure of people to act rationally justifies judicial and governmental intervention.

Mr Obama too spent many years at Chicago, but Mr Presser writes that his views were established while he was a student at Harvard when another movement, “critical legal studies”, was popular. It argued that the law was malleable—a political instrument that had been misused by the powerful in the past and should be reinterpreted to empower the disenfranchised.

The great figure who opposed this approach was Antonin Scalia, who left the Chicago faculty to be a federal appeals court judge then a Supreme Court justice, and whose death almost exactly a year ago created the current opening.

As Mr Presser writes, Scalia believed the law and constitution should be followed by interpreting both as they were understood at the time they were enacted rather than stretched by unelected judges, since original intent was the best means of implementing the will of the people. Change should come through popular votes and the laws enacted by elected legislators. This approach, more than any particular issue, is a fundamental challenge to an expansive court, presidency and even, perhaps, to the aristocratic position that de Tocqueville discerned in the law. As Mr Presser shows, it is a challenge that resonated in unlikely candidates in the past, notably Felix Frankfurter, a Harvard professor, architect of Franklin Roosevelt’s New Deal and a Supreme Court justice, who revealed in his opinions concerns about pushing the boundaries of law too far.

Mr Presser’s book does not always make for easy reading, but the ideas that he has gathered together, all of them put forward by intelligent people, are complex. America is consumed by serious legal debates about issues, what the law says, what people think the law should say—and whether that is law. This may be the book that comes closest to spelling out what is really being argued.