President Barack Obama is choosing a widely respected, combat-hardened commander who led the Afghanistan war coalition during a key transitional period during 2013-14 for the top U.S. military job.U.S. officials say he is nominating Marine Gen. Joseph Dunford Jr. to be chairman of the Joint Chiefs of Staff to succeed Army Gen. Martin Dempsey, who will have served four years in the post.He is well-connected internationally, often meeting with NATO and other coalition leaders, particularly during his Afghanistan command. His selection signals that even as the U.S. puts more focus on Asia and looks ahead to high-tech cyber and space threats, the administration still believes a strong ground force commander is needed to work through conflicts in Iraq, Afghanistan, Syria and across the Middle East and Africa.Obama plans to make the announcement at the White House on Tuesday, said officials who spoke on condition of anonymity because they weren't authorized to speak publicly ahead of the announcement. Dunford, 59, is expected to be easily confirmed by the U.S. Senate.Dunford's service as the commandant of the U.S. Marine Corps will be cut short after he began that job last October. But the rapid promotion is one of several that have marked Dunford's fast-tracked military career, which saw him leap from a one-star general to four stars in about three years.Officials also said Obama is tapping Gen. Paul J. Selva, a top Air Force officer and pilot, to serve as vice chairman. Selva, who has clocked more than 3,100 hours piloting transport and refueling aircraft, is currently the head of U.S. Transportation Command.Dunford began his career as an infantry officer and has commanded at all levels. He served nearly two years in Iraq, including as head of the Marines' 5th Regimental Combat Team during the 2003 invasion, where he earned the nickname "Fighting Joe."If confirmed, Dunford would be only the second Marine to serve as chairman. Gen. Peter Pace, the first Marine chosen as chairman, served one two-year term from 2005 to 2007, but was not renominated by then-Defense Secretary Robert Gates because the Pentagon chief feared a long, difficult Senate hearing focusing on the sharp divisions over the Iraq and Afghanistan wars.Sen. John McCain, Republican chairman of the Senate Armed Services Committee, wouldn't confirm the selection Monday, but he gave the choice a thumbs-up a critical factor for an administration that doesn't want to go through a drawn-out Senate confirmation process.Dunford's most visible role came in 2013 when he was chosen to take over the job as top U.S. military commander in Afghanistan. During his 18 months there, Dunford oversaw the ongoing drawdown of U.S. troops, the transition to Afghan military lead in combat operations, and the tumultuous Afghan elections that dragged on and stalled efforts to reach an agreement on the U.S. military's future presence in the country.