When Gerald Ford picked John Paul Stevens to take the place of William O. Douglas, most people assumed that he had chosen a reliable conservative to replace one of the most flamboyant, activist, and liberal justices in the Court's history. Yet when Stevens announced his retirement, most newspapers called him the leader of the liberal wing of the Court. Stevens personally objected to the idea that he had changed from conservative to liberal over the decades; he had not changed, he declared—the Court had grown more conservative.
There is a great deal of truth in that assertion, but the fact is that Stevens did grow and did change his mind. He has been given the credit for fashioning a number of 5-4 victories for the liberal (or as some would put it, the moderate) wing of the Court, drawing the swing vote, Anthony Kennedy, to their side. In his fifteen years as senior justice, he put together majorities in ground-breaking decisions in favor of gay rights, restrictions on the death penalty, preservation of abortion rights, and the establishment of a role for the nation's judiciary in the fight against terrorism.
It has been hard to categorize Stevens for the simple reason that his opinions rest on the facts and law of the individual case. He has often been sympathetic to the claims of criminal defendants and people who say they were subjected to unlawful discrimination, but he has been skeptical when the government claimed it could not be sued over asserted misconduct. Stevens believes he has not been inconsistent. "There are a lot of things that run through my work over the years that I think are totally consistent. There's a great deal of wisdom to the notion that you try to decide cases narrowly and you let the other decision-makers make as many decisions as they can."
These other decision-makers include Congress, the President, and the states, and Stevens has been a voice of dissent in recent years as the Roberts Court has assumed prerogatives he considered unfounded. He has opposed Originalism, the approach propounded by Antonin Scalia that emphasizes adherence to the original meaning of the constitutional text, and in a memorandum in 1992 wrote "Traditions—especially traditions in the law—are as likely to codify the preferences of those in power as they are to reflect necessity or proven wisdom." Many scholars believe that an important—perhaps the most important—part of Stevens's legacy is his role in the terrorism-related cases that came before the Court as a result of President George W. Bush's policies. Stevens helped to limit the claim of unfettered presidential power and established a baseline of fairness in the detention and treatment of detainees. These cases also reminded both the executive and legislative branches of the importance and function of the Great Writ of habeas corpus.