So far, most Republicans in Congress and some Democrats oppose closing the detention center on the U.S. base in Cuba and releasing inmates or transferring them to prisons inside the United States, The Hill reported.
Dixie Osburn of Human Rights Now said Obama should start transferring inmates immediately to show Congress it can be done.
"He really does need to act now or the window of opportunity he's created could close," she said. "After the 2014 election, the president won't know what Senate or House will be there and whether or not be more or even less receptive to his closing Guantanamo."
A few Republicans support the closing, at least in theory. Sen. John McCain, R-Ariz., visited Guantanamo recently with Sen. Dianne Feinstein, D-Calif., and joined with her in a statement calling for it to be shut down.