By Lawrence Hurley and Mark Felsenthal
WASHINGTON (Reuters) - President Barack Obama on Tuesday will announce three nominees to a key federal appeals court in Washington, the White House said, a move likely to spark confirmation battles in the U.S. Senate.
Obama was due to make the announcement at 10:15 a.m. (1415 GMT) at the White House.
Patricia Ann Millett, Cornelia Pillard, and Robert Wilkins would fill three vacancies on the U.S. Court of Appeals for the District of Columbia Circuit.
Millett is a Washington lawyer who regularly argues before the U.S. Supreme Court. Pillard is a professor at the Georgetown University Law Center. Wilkins is a judge on the U.S. District Court for the District of Columbia.
Obama appointed Wilkins to that court in 2010.
The president has had limited success in shaping the court, often called the nation's second-most important court because it rules on major regulatory issues and hears other high-profile cases.
Last month the Senate voted 97-0 to confirm Sri Srinivasan, a political appointee in the Justice Department, to fill a vacancy on the 11-member body. He was the first Obama appointee to the court.
Another nominee, New York lawyer Caitlin Halligan, withdrew from consideration in March after Republicans twice blocked a vote on her confirmation.
Once Srinivasan joins, the court's eight judges will be equally divided between Democratic and Republican appointees.
Senate Republicans argue that the other three seats need not be filled because the court does not have a heavy workload.
Senator Charles Grassley of Iowa, the top Republican on the Senate Judiciary Committee, has even introduced legislation that would permanently eliminate the three judgeships.
It was "hard to imagine" why Obama needed to fill those vacancies "unless your goal is to pack the court to advance a certain policy agenda," Grassley said in a statement on Monday.
Obama has had fewer judicial nominees confirmed at this stage of his presidency than either George W. Bush or Bill Clinton.
(Reporting By Lawrence Hurley and Mark Felsenthal; Editing by Howard Goller and Xavier Briand)