John Paul Stevens will certainly go down in history as one of the most important liberal Supreme Court justices. But the jurist was also significant to conservatives in a way that continues to reverberate through today's contentious judicial confirmation hearings.

Stevens, who died on Tuesday at the age of 99, eventually led the liberal bloc on the nation's highest court. But he was nominated to the Supreme Court by President Gerald Ford, a Republican. And while Ford's GOP was not as homogeneously conservative as the party is now, neither he nor most of his supporters intended to appoint the most liberal member of the Supreme Court.

On issues like affirmative action and the death penalty, Stevens' leftward shift was more gradual, as he originally voted with the court's conservatives. But he was a strong supporter of federal power over the states and frequently voted to uphold gun control laws, in one case excoriating the dominant conservative judicial philosophy while dissenting against an expansive reading of the Second Amendment. (In retirement, he called for the amendment's repeal.) Conservative Washington Post columnist Henry Olsen complained, "Republicans such as Stevens were thus relatively untrained in serious legal thought when they were elevated to the bench."

Yet Stevens was part of a larger pattern that informs conservatives' Supreme Court strategy today. Some of the most liberal justices of the the post-World War II era — Earl Warren, William Brennan, Harry Blackmun, Stevens, and David Souter — were selected by Republican presidents, who frequently lamented their choices later. Even when the presidents and their judicial picks started getting more conservative under Ronald Reagan, only about half the Supreme Court justices chosen were reliable originalists.

President Ronald Reagan promoted William Rehnquist and nominated Antonin Scalia, for example. But he also put Sandra Day O'Connor and Anthony Kennedy on the Supreme Court. O'Connor and Kennedy were both more conservative than Stevens and the others described in the previous paragraph. But they were also frequently swing votes who upheld some of the most controversial liberal precedents, including Roe v. Wade.

By the 1980s, millions of Americans were voting for Republican presidential candidates in order to overturn Roe. Yet that decision ushering in legal abortion was authored by a justice nominated by a Republican president (Blackmun, chosen by Richard Nixon). Its core holding was affirmed in a decision written by another Republican president's nominee (Kennedy, chosen by Reagan). Stevens usually joined them as part of the bloc that voted to uphold liberal precedents and dissent from conservative decisions. To find a Democratic-appointed justice who turned out to be a surprise conservative, you have to go all the way back to Byron White, nominated by John F. Kennedy in 1962.

This gave rise to conservative groups like the Federalist Society, who carefully scrutinized the records and judicial philosophy of Supreme Court prospects. And if the high court was often a disappointment to conservatives, Republican presidents increasingly began seeding the lower courts with judges whose legal and constitutional philosophies were more congenial. Republican senators, who still overwhelmingly voted for both of Bill Clinton's Supreme Court nominees after the borking of Robert Bork and the near-borking of Clarence Thomas, got stricter too, all the way up to not granting Barack Obama nominee Merrick Garland a hearing.

It all really came to a head under another Republican president, George W. Bush. The younger Bush, who was popular with social and judicial conservatives, initially nominated Harriet Miers to replace O'Connor in 2005. Instead of falling in line, however, conservative groups rejected her as unreliable. They did not want another John Paul Stevens. Conservatives decided they not only should resist Democratic nominees, who proved consistently liberal, but that they could not trust Republican picks either. Miers was withdrawn and replaced with Samuel Alito, whose conservative credentials were far better established.

Without the Miers precedent, it is hard to imagine Republicans who had voted in large numbers to confirm Ruth Bader Ginsburg holding firm on blocking Garland. The failure to even really consider Garland in turn paved the way for the close Senate vote on Neil Gorsuch and eventually the highly charged Brett Kavanaugh hearings.

Donald Trump was less of a philosophical conservative than either Reagan or Bush 43. But he ran on a list of conservative-vetted Supreme Court nominees he would choose from and has so far kept those promises. The result is a rightward shift in the federal judiciary even more pronounced than Reagan's.

There is still an air of unpredictability to these lifetime appointments. Conservatives were outraged by John Roberts' ObamaCare decision and, more recently, the citizenship question on the census. It is by no means clear either Roberts or Kavanaugh would overturn Roe, as many conservatives want. But they are unlikely to lead the liberal bloc on the Supreme Court anytime soon.

The climate in which a Stevens or Scalia could be unanimously confirmed is gone for the foreseeable future. So is the likelihood a Republican president would knowingly nominate someone closer to Stevens than Scalia. Stevens' long tenure on the court is a major reason for both phenomena.