As Senate Democrats begin limbering up for next month’s confirmation hearing of Judge John Roberts, they’d do well to refresh themselves with the 1993 hearings for Justice Ruth Bader Ginsburg. Despite her record as a liberal activist, all but three Republican senators voted for her. She was confirmed 96-3. The upper chamber understood that its role is to vet a candidate’s qualifications. Ideology is the president’s job.

Justice Ginsburg had been a lawyer for the American Civil Liberties Union where she’d questioned laws against prostitution and bigamy. She told senators the only appropriate place for her to discuss hot-button issues was if they appeared before her on the Court. Republican senators respected this. After only four days of hearings the Senate Judiciary Committee concluded she was a talented lawyer and approved her nomination for the Senate to consider. Progress for America, a group supporting the Roberts nomination, helpfully provides video highlights of the Ginsburg hearings at JudgeRoberts.com.

Since Senate Democrats argued for Republicans to respect the rules Justice Ginsburg set for her hearings, one would expect them to do the same for Judge Roberts. Wishful thinking. Instead many Democrats and liberal organizations have indicated they’re aiming for a repeat of the bitter confirmation hearings for Judge Robert Bork in 1987. Senator Schumer has presented Judge Roberts with a list of questions to sound out his ideological views.

These opponents of Judge Roberts believe he is a right-wing ideologue. They cite that he worked for the Reagan administration, that he may have been a member of the Federalist Society, and that his wife is involved in an anti-abortion group. Hardly a list that’s likely to frighten most Americans, but even if he is a right-wing ideologue, so what? That Justice Ginsburg was a member of the left-wing ACLU didn’t matter to Republicans, who focused on her qualifications.

As for his qualifications, his resume speaks for itself: He clerked for Justice Rehnquist, served as associate counsel to President Reagan, and served as principal deputy solicitor general to the first President Bush. He’s argued an impressive 39 cases before the Supreme Court. When he was nominated in 2003 to ride the District of Columbia Circuit for the U.S. Court of Appeals, 156 members of the local bar – from both sides of the political divide – wrote to the Senate Judiciary Committee that he represented the “best of the bar.”

Even the American Bar Association, a liberal pressure group, agrees on Judge Roberts’s suitability. It announced Wednesday that Mr. Roberts had been given their highest ranking – “well-qualified” – to sit on the Supreme Court. How Mr. Schumer and his colleagues conduct Judge Roberts’s confirmation hearings will be a test of their qualifications – whether they have the integrity and consistency their constituents expect of them – and will be watched for years to come.