Has pancreatic cancer, which leads to speculation about a possible replacement should the need arise.
If Justice Ginsburg is forced from the court for health reasons, it would increase the possibility of a second vacancy from among her aging colleagues, like Justice John Paul Stevens, who will turn 89 in April.
In preparation for a vacancy, senior Obama advisers have already discussed possible candidates. Many lawyers and court scholars believe that Mr. Obama would be obliged to choose a woman as his first court selection. If Justice Ginsburg were to leave the court, the political imperative to choose a woman would only increase.
Among women on the list of possible candidates are Sonia Sotomayor, a federal appeals court judge in New York; Diane P. Wood, a federal appeals court judge in Chicago; and Elena Kagan, who was the dean at Harvard Law School and was recently nominated to be solicitor general.
Other possible candidates, say court watchers, academics and lawyers, is Deval Patrick, the governor of Massachusetts, a friend of Mr. Obama and a former Justice Department official; Harold Hongju Koh, the dean of the Yale Law School; and Merrick B. Garland, a federal appeals court judge in Washington.
The list also includes Cass R. Sunstein, a law professor at Harvard and former colleague of Mr. Obama at the University of Chicago Law School who has been named administrator of the Office of Information and Regulatory Affairs.
This is the closet we get to the death watch monarchies and totalitarian regimes suffer through.
