John Roberts is likely about to occupy a dual position that no one else has in the modern history of the United States: He will be both the court’s chief justice and, with the retirement of Justice Anthony Kennedy, its median voter — the person in charge of the court, and the justice most likely to swing a decision one way or the other. This combination of institutional power and ideological centrality will give Roberts remarkable sway over the business and decisions of the court, and by extension the law of the land, possibly for decades to come.
But liberals cannot reasonably hold out much hope that Roberts will sway votes for some of their favored causes the way Kennedy did. While the statistical metrics show Roberts taking a relatively moderate position, he has very rarely voted with the liberals when it mattered.
Roberts, 63, took his seat on the bench in 2005, after then-President George W. Bush appointed him. Like Kennedy, he has proven solidly conservative on major American issues such as voting rights, campaign finance and gun control. Unlike Kennedy, Roberts dissented in the case that legalized gay marriage, dissented in the case that found executing an intellectually disabled person to be unconstitutional, and dissented in the case that affirmed that California must reduce its overcrowded prison populations, to name but a few examples.
All cases Close cases justice Total Conservative rulings Percent conservative Total Conservative rulings Percent conservative Thomas 1,918 1,270 66.2 427 342 80.1% Scalia 2,461 1,566 63.6 583 472 81.0 Alito 768 485 63.2 182 153 84.1 O’Connor 2,484 1,483 59.7 567 419 73.9 Roberts 800 463 57.9 188 155 82.4 Kennedy 2,361 1,344 56.9 537 383 71.3 Breyer 1,624 675 41.6 379 81 21.4 Souter 1,497 594 39.7 337 60 17.8 Kagan 427 164 38.4 94 17 18.1 Stevens 3,515 1,335 38.0 798 178 22.3 Ginsburg 1,727 645 37.3 395 58 14.7 Sotomayor 523 193 36.9 109 11 10.1
Despite his conservative pedigree, Roberts’s ideology has been slipping left in recent years according to the most prominent measure of such things, called Martin-Quinn scores. By this measure, he’s the most moderate conservative remaining on the court, and with President Trump expected to appoint another firm conservative, Roberts will probably remain the only member of the court’s right-wing bloc who approaches a centrist position.
But has Roberts ever really swung? Will he swing in the future?