Shanahan said he made the decision, announced first by U.S. President Donald Trump in a tweet, to prevent his three children from reliving “a traumatic chapter in our family life.”
“It is unfortunate that a painful and deeply personal family situation from long ago is being dredged up,” Shanahan, a former Boeing executive, said in a statement.
Trump said the secretary of the Army, Mark Esper, will be named as the new acting defense secretary. Shanahan had been due to go before the Senate to be confirmed in the Pentagon top job but the alleged domestic violence incidents emerged as the FBI was conducting background checks ahead of a Senate confirmation hearing.
USA Today reported that the FBI had been examining a nine-year-old domestic dispute involving Shanahan and his then-wife.
The newspaper reported that Shanahan said he “never laid a hand on” his former wife. But USA Today reported that both he and his wife had claimed they had been punched by the other.
The Washington Post reported a gruesome incident involving Shanahan’s teenage son allegedly hitting his mother, Shanahan’s ex-wife, with a baseball bat, leaving her unconscious in a pool of blood.
“Bad things can happen to good families . . . and this is a tragedy, really,” Shanahan was quoted telling the Washington Post this week. He added the disclosure of the incident would “ruin my son’s life.”
Pentagon officials could not be immediately reached for comment about the domestic violence reports or about Trump’s announcement.
The decision to stand down, which Trump had said owed to Shanahan’s desire to spend more time with his family, promises to prolong what has already been the longest period without a confirmed secretary of defense. Shanahan was the longest official in history to serve as secretary of defense in only an acting capacity, according to Pentagon records.
Trump’s critics had already questioned whether Shanahan, without Senate confirmation, had the power to stand up to Trump if he had a difference of opinion on military strategy, since his nomination could be withdrawn at any time.
Shanahan did not have prior experience in national security matters before he was picked by then-Defense Secretary Jim Mattis to be his deputy. Shanahan had been in the job, in an acting capacity, since Mattis stepped down at the end of 2018 citing policy differences with Trump.
A source familiar with the situation said Shanahan met Trump in the Oval Office on Tuesday morning, telling him that he wanted to step down. The source, speaking to Reuters on condition of anonymity, said the decision was 100 percent Shanahan’s.
Additional reporting by Makini Brice; Writing by Alistair Bell; Editing by Mary Milliken and Nick Zieminski