The Senate voted on Saturday to confirm Brett Kavanaugh to the Supreme Court after one of the most contentious nomination battles in history and by the slimmest margin for a justice in the modern era.

Now, difficult as this seems, it will be up to the new justice to seek to reassure a country riven over his selection that he has the temperament and judgment to do the job; as important, it will be up to the court as a whole to demonstrate that it is not just another partisan institution. And it will be up to those who opposed his confirmation to evaluate Kavanaugh fairly in his new position.

Many Americans believe, with reason, that the GOP-majority Senate muscled the Kavanaugh nomination through in its drive to install a reliable fifth conservative vote. Now, an increasingly dysfunctional Congress and a wayward presidency threaten to place more demands on this new court to address significant social problems and perhaps even defuse threats to the nation’s constitutional order.

Meantime, a cemented conservative majority will face temptations to wreak big changes in the law. As they confront these challenges, the justices must act as the careful, restrained jurists they claim to be, not the partisans in robes many fear.

Kavanaugh unfortunately earned such concerns in his second Senate confirmation hearing, when he lashed out at Democratic senators and “the Left”. Kavanaugh acknowledged in a Wall Street Journal op-ed that his “tone was sharp, and I said a few things I should not have said”. He vowed that, “going forward, you can count on me to be the same kind of judge and person I have been for my entire 28-year legal career: hard-working, even-keeled, open-minded, independent and dedicated to the Constitution and the public good”.

The new justice will face understandable scepticism about his ability to meet that test. But it is the critical one that he faces and, although we were unable to support his confirmation, one that we fervently hope he passes.

The other justices, too, must recognise that the stakes are different now, with the retirement of swing-vote Justice Anthony Kennedy and after Republicans’ dirty play blocking Barack Obama nominee Merrick Garland from the court. At his own confirmation hearings, Chief Justice John Roberts Jr likened the judicial role to that of an umpire, calling balls and strikes. Yet the Roberts court has since handed down sweeping conservative rulings in some big and politically charged cases. Roberts’s decision to eviscerate the Voting Rights Act stands out. Justice Neil Gorsuch, who took the seat that should have gone to Garland, emphasised the importance of adhering to precedent in his confirmation hearings. Then he voted to rip up a major precedent on union dues. Now, it is more important than ever that the court move with care and discretion.

The country, after all, will get neither from its president. Donald Trump attacked anti-Kavanaugh Capitol Hill protesters on Friday, some of whom claim to have been sexually assaulted themselves, as “paid professionals” and “very rude elevator screamers”. Whether or not you believe Christine Blasey Ford’s sexual assault allegations should have kept Kavanaugh off the court, she sacrificed her life as she knew it to relate her story. Trump only encouraged those assailing Ford, mocking her for failing to remember certain details of her assault. Survivors scared that they will be accused of smearing “a good man” on behalf of some covert agenda now have another reason to hesitate to report their assaults.

That is the sad legacy, so far, of the Kavanaugh confirmation saga. Now Kavanaugh and his colleagues will have an opportunity to fashion a more positive one in the years to come.