In his resignation letter, Sessions took one final jab at the president, writing: "Most importantly, in my time as Attorney General we have restored and upheld the rule of law-a glorious tradition that each of us has a responsibility to safeguard".
Other names that have been floated as possible replacements for Sessions include Rep. John Ratcliffe of Texas, a former federal prosecutor, as well John Michael Luttig, a former US Court of Appeals judge, Justice Department official and current general counsel at Boeing. Mr. Barr, 68, is a former general counsel and executive vice president of Verizon Communications who works now as a lawyer at the firm of Kirkland & Ellis.
Another person familiar with the discussions said Barr is "a really serious contender, and possibly the front-runner" for the job, but stressed it was impossible to predict Trump's pick definitively until it was announced publicly.
Trump's consideration of a new attorney general comes during a critical time for special counsel Robert Mueller's investigation, of which the next Justice Department chief will inherit oversight.
After leaving government, Barr returned to the private sector, where he held several senior executive positions, including with GTE Corporation and Verizon Communications.More news: London share prices PLUMMET amid US-China trade war fears — FTSE latest
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The Mueller probe has been an Achilles heel for the office of attorney general the past couple of years.
While everyone knows that Mr. Trump can change his mind in a heartbeat, the general feeling among those close to the matter, is that a decision on Barr could take place within a matter of days. He was promoted to deputy attorney general next, and then to the top role.
Barr not only said that an investigation of this would be above-board, he claimed it was necessary in the interest of justice.
Barr has criticised Mueller for hiring attorneys for his team who contributed to Democratic politicians, including Hillary Clinton. He also worked at the Central Intelligence Agency in the 1970s and in the Reagan White House in the early 1980s.
"In my view, prosecutors who make political contributions are identifying fairly strongly with a political party ..."