The three days of testimony from Supreme Court nominee Brett Kavanaugh that concluded on Thursday were less a showcase for Kavanaugh, who delivered a steady, if evasive, performance, than a depressing display of the breakdown of Senate norms.Kavanaugh dodged question after question, frustrating senators attempting to pin him down on relevant legal issues. He said he had not studied whether the president can pardon himself. On whether the president can order the Justice Department to investigate - or not investigate - someone based purely on political considerations, Kavanaugh said he should not comment on "the latest political controversy." Yet these are pressing legal matters and Mr. Kavanaugh’s views are of rightful interest.To his credit, the nominee embraced the crucial 1974 United States vs. Nixon decision, which forced President Richard M. Nixon to turn audio recordings over to the Watergate special counsel. Yet Kavanaugh should have done more to reassure senators that, under current circumstances, he does not believe an errant president is due extraordinary deference. On Roe vs. Wade, Kavanaugh came as close as he could — without making any clear commitments — to saying he would not be the decisive vote to overturn the precedent, stressing that the court not only established a right to abortion but also repeatedly reaffirmed it. But it still left him room to rule for states wishing to regulate away abortion without formally banning it.Kavanaugh’s lack of specificity was most concerning on whether he should recuse himself from cases involving President Donald Trump. "I should not and may not make a commitment," he said. But that should not have stopped him from offering more detail about his thinking. He should have tried to dispel legitimate concerns that Trump picked him specifically so he would vote to block investigations of the president’s actions.In the past, Supreme Court nominees have been less than forthcoming. But in Kavanaugh’s case, the stonewalling was compounded by Republicans’ refusal to wait for relevant documents to be released. Some documents were leaked to the New York Times in the middle of the hearings. Two Democrats distributed documents they believed should have been on the record from the beginning. Though they offered no disqualifying revelations about Kavanaugh, they nevertheless contained material relating to abortion, his past work vetting judicial nominees, and other relevant topics. Nothing in them appeared to justify hiding them from the public.Republicans’ refusal to allow an orderly and transparent process cast a shadow on the whole proceeding. Democrats resorted to hints about what sealed documents might show, such as when Sen. Kamala Harris, D-Calif., warned the nominee to be very careful about how he answered a question about any potential past contact with Trump-connected lawyers. Last-minute document dumps only compounded the absurdity.Nothing Democrats or Republicans have done before has more poisoned the Supreme Court confirmation process, perhaps irrevocably, than Republicans’ blocking of Merrick Garland, President Barack Obama’s nominee, and their subsequent effort to rush through Kavanaugh. It is a shame two distinguished jurists have been caught in a disgusting partisan spectacle.