Roberts, however, is not by temperament a “swing” justice. His hesitations about moving the Court (and the country) to the right, it appears, are largely a question of pace; he believes that it is better to proceed slowly toward dismantling the New Deal, legislative protection of civil and voting rights, environmental protections, the remaining regulation of campaign finance, and the remaining shreds of the right of reproductive choice.

This solicitude for constitutional etiquette and the nonpartisan image of the federal courts is the most important thing that separates Roberts from the Trump administration, the other four conservative judges, and the extremists ensconced by Trump on the lower courts. What these other players have coveted for a generation, and now have, is power, and they are eager to use it…

Roberts might have to decide whether to sacrifice his conservative credibility a second time to protect the Court from the opprobrium of scuttling the nation’s health-care system. There’s little doubt that the other four conservatives would be delighted to take the act down, consequences be damned. Adding complexity: By the time the case reaches the Supreme Court, Roberts may no longer even be the swing vote. It’s quite possible that Trump will fill another Supreme Court vacancy before 2021. If that happens, or if Trump is reelected, Roberts will assuredly have to choose either to join his Court’s rapid move to the right or to condemn himself to irrelevance. His record suggests he is unlikely to remain a solitary figure seeking to block the triumph of legal conservatism.