If a Supreme Court vacancy arises with the GOP in control of the Senate, Obama may be inclined to put forward a “really safe pick,” such as Patricia Ann Millett, a widely praised judge on the Court of Appeals for the District of Columbia Circuit, Millhiser said.

Obama may be less likely to nominate someone more in the mode of Ginsburg, such as Judge Cornelia “Nina” Pillard, another member of the D.C. appeals court whom Millhiser called “arguably the preeminent women’s rights litigator of her generation” and his own personal top choice for the court.

Republicans “can skim a few potential nominees off the top if they control the majority,” Millhiser warned.

If a Ginsburg retirement announcement were to come this year, recent history suggests it would occur soon — or would have occurred already.