In the end, however, no one doubts that Ginsburg would support same-sex marriage. In August, she officiated at the marriage of the Kennedy Center's president, Michael Kaiser, to his male partner.
Both Kennedy and Ginsburg pay close attention to the trends in the states and in the courts. And on same-sex marriage, the tide has been flowing in one direction. Currently, 17 states and the District of Columbia allow gay couples to marry.
Political opposition to same-sex marriage also has waned. Rather than criticizing gay people, some Republican leaders have emphasized the importance of letting voters have the final word.
Ed Gillespie, the former Republican Party chairman who is running for a Senate seat in Virginia, faulted the judge for intervening in such a contentious issue.
"This is a matter the people of Virginia should be free to decide, rather than having a federal judge impose law by judicial fiat," he said in a statement Friday.
Another indication came this month from Indiana, where the Republican-controlled Legislature decided not to put a constitutional ban on same-sex marriage on the ballot this fall. The measure has been put off until at least 2016.
So far, the recent rulings on marriage have come from federal district courts. Before any case gets to the Supreme Court, the intermediate level appeals courts will weigh in.
The U.S. 10th Circuit Court of Appeals in Denver will go first, with oral arguments scheduled for April on the cases from Oklahoma and Utah. The Virginia ruling will go to the U.S. 4th Circuit Court of Appeals in Richmond, Va., and the Kentucky case will go to the U.S. 6th Circuit Court of Appeals in Cincinnati. The U.S. 9th Circuit Court of Appeals, based in San Francisco, has a pending appeal from Nevada but has not scheduled arguments.
Once an appeals court hands down a decision, the losing side will have 90 days to file an appeal in the Supreme Court. As a result, a ruling that comes this summer could easily reach the justices in time for a decision in 2015.