Retired U.S. Army four-star General Lloyd James Austin has accepted the offer of president-elect Joe Biden to become the country's next Secretary of Defense.

If his nomination passes the Senate, Austin will become the first African American to hold the Pentagon's top post. Biden's selection of Austin was praised for its history-making aspect but also criticized as favoring another retired general for a job that traditionally goes to a civilian. President Donald Trump's first defense secretary, James Mattis, was also a retired four-star general in the U.S Marines. 

Biden is said to have been drawn to Austin because he trusts the retired general since they worked together when Biden served as vice president and was also responsible for foreign policy. Austin is also crisis-tested and respected across the military.

"He also appreciated that General Austin knows the human costs of war firsthand," said one source,

Austin's extensive logistics experience from his time in the Army might also prove critical as the military helps distribute COVID-19 vaccines nationwide, said a source close to Biden.

Biden's team also sees Austin as the safe choice, said a former defense official. Austin can be relied on to be a good soldier who would carry out Biden's agenda.

Some national security experts, however, question the wisdom of having another military man heading the civilian Department of Defense, again further eroding civilian control over the U.S. Armed Forces.

"From a civil-military relations perspective, this seems like a terrible idea," tweeted Rosa Brooks, a Georgetown University professor and former Pentagon official who wrote an op-ed in The New York Times calling for a woman to be chosen as Defense secretary.

"Lots of damage during the Trump era. Especially after Mattis, Kelly, McMaster, Flynn.... putting a recently retired 4 star, no matter how wonderful, into the top civilian DoD position sends the worst possible message."

Sources close to Biden and privy to the information revealed Austin's selection to select U.S. media. Austin's appointment will somewhat assuage African Americans dismayed by their under representation in the new Biden Cabinet.

Austin edged out former Homeland Security Secretary Jeh Johnson for the job after it became clear Johnson's close association with former president Barack Obama and his record might be an impediment to his confirmation.

Austin, however, will need a congressional waiver of the National Security Act of 1947 to bypass the seven-year waiting period after a nominee for secretary of defense leaves the active-duty military. This condition is prescribed by Title 10, Section 113 of the United States Code.

Such a waiver has only been granted twice in U.S. history: to Mattis in 2017 and to George Marshall in 1950. Adding Austin's name to this list might take a lot of doing considering Mattis took on the job less than four years ago.

Austin retired from the Army in 2016 after 41 years of service starting as a second lieutenant with the U.S. 3rd Infantry Division.

Austin was the 12th commander of United States Central Command and the first African American to head this major military command. Before this, Austin served as the 33rd vice chief of staff of the U.S. Army from 2012 to 2016.

He was also the last commanding general of United States Forces-Iraq, Operation New Dawn, which drew down on Dec. 18, 2011. Austin was then appointed Vice Chief of Staff of the U.S. Army before his retirement.