Acting Defense Secretary Patrick Shanahan has withdrawn himself from the confirmation process, effectively stepping down from the role.

President Trump made the announcement on Twitter Tuesday, writing: “Acting Secretary of Defense Patrick Shanahan, who has done a wonderful job, has decided not to go forward with his confirmation process so that he can devote more time to his family.”

Trump also announced that Secretary of the Army Mark Esper will replace Shanahan. Esper, a former executive at defense giant Raytheon, was confirmed as army secretary in November 2017.

“I thank Pat for his outstanding service and will be naming Secretary of the Army, Mark Esper, to be the new Acting Secretary of Defense,” Trump wrote. “I know Mark, and have no doubt he will do a fantastic job!”

Shanahan released a statement after the news broke, explaining that his decision to step down was due to the confirmation process’ background check. His confirmation was delayed by a lengthy FBI investigation into a decade-old domestic abuse allegation, according to reports.

The acting defense secretary reportedly has worked to keep the incident, along with one involving his wife and son, out of the public eye, The Washington Post reported Tuesday.

In 2010, Shanahan’s now former wife Kimberley Jordinson was arrested for allegedly punching him in the face. At the time, she reportedly told police that Shanahan had punched her.

In a separate incident, Shanahan’s son was arrested for allegedly hitting his mother with a baseball bat.

According to Shanahan, the dredging up of a “deeply personal family situation from long ago” was being portrayed in a “misleading way.”

“I never laid a hand on my then-wife and cooperated fully in a thorough law enforcement investigation that resulted in her being charged with assault against me,” Shanahan wrote. “... I wish nothing but the best for her and regret that my children's privacy has been violated and they are being forced to relive a tragic situation that we have worked so hard as a family to put behind us.”

Shanahan told The Washington Post that bringing up the incidents in a public confirmation process would “ruin my son’s life.” “Bad things can happen to good families . . . and this is a tragedy, really,” he said.

In 2011, Jordinson and her 17-year-old son William got into “a verbal dispute” over her suspicion that the was in a romantic relationship with a 36-year-old woman, according to a police report. The fight escalated and became physical when William “shoved and pinned his mother against a bathroom wall” before striking her with a baseball bat multiple times, the report says.

William allegedly struck several blows to his mother’s head and torso and left her “to lie in a pool of blood” and then “unplugged the landline phone cord depriving the victim... the use of 911 to render aid.”

“I attempted to run away from Will, but as I reached the laundry room, he struck me with the bat in the back of my head,” Jordinson wrote in a divorce filing. “The last thing I remember from before I lost consciousness is the impact of the bat, and blood gushing everywhere.”

Shanahan was quick to defend his son’s actions, and two weeks after the attack he sent his ex-wife’s brother a memo arguing that his son had acted in self-defense. “Use of a baseball bat in self-defense will likely be viewed as an imbalance of force,” Shanahan wrote to his brother-in-law at the time. “However, Will’s mother harassed him for nearly three hours before the incident.”

The attack left Jordinson with a fractured skull and elbow, according to the police report.

Shanahan recently told the Post that he no longer defends his son’s actions, and does not believe there is any justification for assaulting someone with a baseball bat.

Shanahan was seen as a controversial choice when he was picked to temporarily replace famed former Marine Gen. James Mattis in December, due to his past as a Boeing executive in charge of the company’s missile program.

This is the longest period the United States has gone without a confirmed secretary of defense. Along with defense secretary, the Trump administration currently lacks a homeland security chief, a United Nations ambassador, and a White House chief of staff.