It is a curious standard to maintain in this context. What would be the response if a nominee insisted that corporate parties “have a right to be believed” or people had a right to be believed based on their race or their religion? Indeed, judges received far more detailed allegations in the form of complaints in every case but maintain their strict neutrality in judging the case until after testimony and evidence has been fully placed into the record. A statement that a judge “believes” one party would be grounds for immediate removal for a lack of impartiality.
It is certainly true that senators are not judges, but they have repeatedly acknowledged their obligation to allow for a fair hearing. A hearing on an allegation of this kind comes closest in the Senate to a judicial proceeding other than an impeachment trial. Witnesses appear in the expectation that the committee will afford both parties the basic protections of due process, including an open mind. It is not enough to say that your mind can be changed but you are starting with a belief that Ford is telling the truth and Kavanaugh is a liar…
Moreover, it is possible to believe Ford while believing that she could be mistaken on the identity of the attacker. It is possible to pass a polygraph examination with a false memory or association.
By the same token, the fact that Kavanaugh can produce former girlfriends and dozens of women who speak highly of him is of little import in judging these facts.