Two people appeared before the US Senate judiciary committee on Thursday. One was poised, dignified, composed but not practised, polite yet firm, and in spite of the unspeakably difficult conditions managed to deliver a consistent account laced with scientific expertise. The other was a vision of uncontrolled anger: aggressive, partisan, rude, rambling, evasive, by turns defiant and self-pitying.

Tragically for the United States, the first was Christine Blasey Ford, whose claims of sexual assault the judiciary committee refused to entertain seriously, let alone submit to rigorous investigation. And the second was Brett Kavanaugh, the man she accuses of groping her and covering her mouth with his hand when she tried to scream. A man who is on course to ascend to the highest levels of American power. If the Republican Party succeeds in pushing though his nomination to the supreme court, Kavanaugh will be the swing vote that decides on the most contentious questions facing the modern republic for decades to come.

Republicans complain about a lack of evidence to support Blasey Ford’s allegation that Kavanaugh sexually assaulted her in the 1980s. Yet those same republicans appear to be doing everything in their power to suppress any evidence there might be. Blasey Ford took a polygraph test, has called for an FBI inquiry and has supported calls for a man she says witnessed the incident to be compelled to testify. Kavanaugh has resisted all three, and so have his republican sponsors. On Thursday the 11 Republican men on the committee listened to Blasey Ford’s devastating testimony and concluded that even postponing a vote for a few days was too much to ask.

The hearing did not – could not – establish whether the incident as described by Kavanaugh’s accuser took place as she outlined it. As Blasey’s testimony ended, then, senators’ judgment as to Kavanaugh’s suitability for high judicial office rested on their assessment of Blasey Ford’s credibility. Did her account disqualify him? A few hours later, having watched Kavanaugh’s performance, no morally serious observer could have come to any other conclusion but that Kavanaugh had disqualified himself. Gone was the veneer of bipartisan impartiality, of judicial reserve. The hearing was “a national disgrace”, he shouted, eyebrows arched, features contorted. He was the victim of a plot by Democrats determined to avenge Hillary Clinton’s election defeat, Kavanaugh ranted. Not for a minute did he appear to countenance that Democrats might actually believe Blasey Ford. The insight into his temperament was telling: this was not the performance of a judge but a tribal party loyalist masquerading as one.

Kavanaugh was right about one thing: the hearing was a disgrace. And his elevation to the supreme court would be an even greater one.