A constitutional law expert believes a federal appeals judge in Washington, DC, is the frontrunner to replace liberal Supreme Court Justice John Paul Stevens.

Justice Stevens is expected to retire by the end of the high court's current term, April 28 -- and Curt Levey, executive director of the Committee for Justice, believes Obama is likely to appoint a man to replace Stevens.

"When [Ruth Bader] Ginsburg retires, which will happen very soon, there will be a lot of pressure to appoint a woman," Levey comments. "And so if he appoints a woman now, that's three women in a row -- which isn't a bad thing, but it sort of limits your choices when you have to appoint three women in a row or three anything in a row"...