Obama plans to announce Johnson's nomination Friday. He must be confirmed by the Senate before taking over the post most recently held by Janet Napolitano, who stepped down in August to become president of the University of California system.
As general counsel at the Defense Department during the wars in Iraq and Afghanistan, Johnson was an aggressive advocate on a number of complex and contentious legal issues. He oversaw the escalation of the use of unmanned drone strikes, the revamping of military commissions to try terrorism suspects rather than using civilian courts and the repeal of the military's ban on openly gay service members. He also mapped out the legal defense for the American cross-border raid into Pakistan that killed Osama bin Laden.
A senior Obama administration official on Thursday confirmed Johnson's selection, first reported by The Daily Beast. The official was not authorized to speak about the nomination on the record and spoke on condition of anonymity.
The official said Obama chose Johnson because of his experience as a national security leader. The official noted that Johnson oversaw the work of more than 10,000 lawyers and was responsible for reviewing every military operation approved by the president and defense secretary.
Johnson is not as well versed in the immigration and disaster response side of the Homeland Security Department, although the administration official pointed out the Pentagon also coordinates federal relief to respond quickly to disasters.
At the Pentagon, Johnson was involved in the decision to move Army Pfc. Chelsea Manning from a military jail in Quantico, Va. to Fort Leavenworth, Kan. Supporters of Manning, the young soldier who leaked thousands of classified documents to WikiLeaks, said conditions at the military jail in Virginia were too harsh.
Johnson led a widespread crackdown on unauthorized leaks in the Defense Department, including warning former Navy SEAL Matt Bissonnette that by publishing a book on the SEAL's raid that killed bin Laden he was in "material breach" of two nondisclosure agreements he signed earlier in his career. He was also involved in the investigation of retired Marine Gen. John Allen and Tampa, Fla., socialite Jill Kelley.
Johnson sparked criticism when he said in a speech at Britain's Oxford University last November that the war on terror was not an endless conflict and that the U.S. was approaching a "tipping point" after which the military fight against al-Qaida would be replaced by a law enforcement and intelligence operation.
"War must be regarded as a finite, extraordinary and unnatural state of affairs," Johnson said. "In its 12th year, we must not accept the current conflict, and all that it entails, as the new normal."
Johnson was part of the team that looked at ways to bring women into combat missions and which assessed legal questions surrounding sexual assaults in the military, including how the chain of command should be involved in investigations and prosecutions. He also helped pave the way for the military's 2010 repeal of the "don't ask, don't tell" policy banning openly gay service members.
"For those service members who are gay and lesbian, we lifted a real and personal burden from their shoulders," Johnson said last year at an event recognizing the service of gay troops. "They no longer have to live a lie in the military."
Johnson, a former assistant U.S. attorney who also was Air Force general counsel under President Bill Clinton, left the Obama administration in 2012 and returned to private practice.
According to a bio on the website of his law firm, Paul, Weiss, Rifkind, Wharton & Garrison LLP, his civil and criminal clients have included Citigroup, Salomon Smith Barney, R.J. Reynolds Tobacco Co. and Gillette.
Johnson is a 1979 graduate of Morehouse College and a 1982 graduate of Columbia Law School.
Associated Press writers Alicia A. Caldwell and Lolita C. Baldor contributed to this report.
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