Mr. Chermerinsky, 60, makes a valid point. Historically, the Senate does not filibuster Supreme Court nominees (the only exception being the manner in which Justice Abe Fortas was blocked from becoming the chief justice), but a majority rejecting a nominee on the basis of ideology? That does happen, and in the tea party era, Republicans like Texas Sen. Ted Cruz look to be itching for such a fight. If Justice Ginsburg wishes to protect her legacy, resigning now would make some sense. On any number of fronts important to progressives, including gay marriage, recent 5-4 decisions have depended on four liberal justices being joined by Justice Anthony M. Kennedy. Make it three liberal justices, and suddenly that Kennedy swing vote no longer swings a majority.