Sen. Jim DeMint, R-S.C., had led the opposition to Southers, who was hailed by law enforcement and union officials and had support from Senate Homeland Security and Governmental Affairs ranking member Susan Collins.
DeMint had raised questions about whether Southers would support efforts to unionize TSA screeners. DeMint and a handful of other GOP senators also complained that he was not forthcoming about improperly accessing FBI data 20 years ago.
Southers, a 30-year veteran of public safety and counterterrorism programs at the local, state and federal level, won unanimous approval in November from the Senate Homeland Security and Governmental Affairs.
Prior to receiving the committee's endorsement, Southers admitted in an affidavit that he had been censured by FBI higher-ups 20 years ago for asking a San Diego police employee to run a background check on his estranged wife's then-boyfriend.
But after the panel approved his nomination, Southers wrote a letter to senators saying that he actually had twice run background checks himself.
In a statement, Southers said his nomination "has become a lightning rod for those who have chosen to push a political agenda at the risk of the safety and security of the American people. This partisan climate is unacceptable and I refuse to allow myself to remain part of their dialogue."
Southers is assistant chief in charge of security and intelligence at Los Angeles International Airport's police department. In addition to serving at the FBI, he also was deputy director of the California Office of Homeland Security.