Kavanaugh’s behavior has irrevocably marked his possible tenure on the Court. With such a partisan route as his pathway, a Justice Kavanaugh would arrive at the Supreme Court as a patient zero, carrying a virus of illegitimacy to its decisions. Since Kavanaugh declared his hostility to the Democratic Party and the left so openly and with such ferocity, it has seemed inevitable that tens of millions of Americans will never see him as an impartial judge.

That would create a stark equation for Roberts, who must surely realize that much—perhaps most—of the nation would question the validity of every 5–4 party-line decision in which Kavanaugh would provide the deciding vote. In the past, fear of further eroding the Court’s legitimacy has provided a limited (though hardly uniform) check on Roberts’s willingness to force major decisions on party-line votes. But if the Senate confirms Kavanaugh, it will present Roberts with a justice whose every decision will be viewed through the lens of the partisan and tribal animosities he inflamed to defend his nomination.

Every time Roberts would lean on Kavanaugh to construct a majority, the chief justice could further erode the Court’s already eroding public confidence. Before the disputed Bush v. Gore decision, which ended the recount in the 2000 presidential election, about half of Americans routinely expressed a great deal of confidence in the Court, according to Gallup polling. That number has fallen to 40 percent or less since the mid-2000s; in the latest Gallup measurement, from June, just one-third of Democrats said they had faith in the Court, compared with about two-fifths of Republicans. In a separate Gallup measure of job approval, the share of Republicans who gave the Court positive marks (67 percent) was almost double the portion of Democrats (36 percent).

No matter how his hearings unfolded, Kavanaugh’s nomination was destined to heighten the political storms around the Court. He would create an all-male, five-member, Republican-appointed majority that could control the Court until the 2030s; its oldest member, Clarence Thomas, is only 70. Kavanaugh was also chosen to create a more reliably conservative majority than was possible under Anthony Kennedy, who broke from his fellow GOP justices on some key issues (though less so in his final year).

The replacement of Kennedy with Kavanaugh was always a recipe for future conflict, because it would increase the likelihood of years of 5–4 party-line votes to reject liberal legal priorities, whether that’s voting rights, environmental regulation, balancing the rights of defendants and law enforcement, or preserving legal access to abortion. Adding to the tension, Kavanaugh’s record signals he could provide the decisive vote for the majority to block efforts at opening more employment and educational opportunities to minorities through affirmative action and other diversity programs, even as nonwhites become a majority among young people. Looming over his nomination, too, was Democratic bitterness at Republicans’ refusal to even consider Merrick Garland, the appellate-court judge whom former President Barack Obama nominated for a Supreme Court vacancy.