The senators tasked with vetting Acting Secretary of Defense Patrick Shanahan say they were unaware of the accusations of domestic violence in his family that led to his resignation Tuesday. The altercations never came up during Shanahan’s 2017 confirmation hearing for the position of Deputy Secretary of Defense, lawmakers told The Daily Beast, nor did it arise as he was preparing to assume the role of Pentagon chief permanently.

“We’ve been wondering why we have not gotten an FBI report. It has seemed slow to us. And now we understand why,” said Sen. Tim Kaine (D-VA), a member of the Senate Armed Services Committee, adding that he “didn’t know” about Shanahan's ex-wife’s arrest for punching Shanahan in the face, nor his son’s arrest for attacking his mother with a baseball bat, until reports surfaced in USA Today and the Washington Post about the alleged incidents.

President Donald Trump nominated Shanahan, a former Boeing executive, for defense secretary in March 2019. Since then, his confirmation process lingered, leaving the Pentagon without a confirmed leader for the longest stretch in history and raising concerns among lawmakers who were told that the postponement was partly because of a hold up by the FBI. At least one of those lawmakers called for an investigation on Tuesday as to why they had not been told by the administration about Shanahan’s past.

“I want to know what was known, and whether it was fully disclosed,” Sen. Richard Blumenthal (D-CT), who also sits on the armed services committee, told The Daily Beast. “It was material to this nomination when he was proposed for deputy secretary, as well as named his nominee as secretary, although the full paperwork was never sent to us.”

The administration is supposed to turn over all relevant docs pertaining to a nominee’s background check. But that didn’t happen, according to a former Senate Armed Services Committee staffer.

“This never came up the first time around [when Shanahan was nominated to be Deputy Defense Secretary in 2017]. Trust me, I’d remember. And the FBI vetting process is thorough. We would routinely get things like a nominee who had tried coke once in the 1980s,” the ex-staffer told The Daily Beast.

“If these domestic issues are as serious as being reported, SASC would have been told,” the ex-staffer added. “And I would know. Which leads me to conclude that this stuff was never reported to the committee. Not sure why that happened, but I see no other explanation.”

Shanahan announced Tuesday that he would no longer seek to be confirmed as Defense Secretary and would be resigning from his post at the Pentagon. The news came as reports surfaced that he had downplayed his son’s assault on his ex-wife, and that both he and his ex-wife had both claimed, back in 2010, that they had been punched in the face by the other after drinking. Part of the altercation reportedly took place in front of their home in Seattle. USA Today obtained recordings from the night of the incident.

“My husband is throwing punches at me,” Shanahan’s ex-wife Kimberly Jordinson told a 911 offcer, according to USA Today. “He’s been hitting me… I don’t need a medic, I need you guys to get him out of the house… He’s just swinging punches at me.”

Shanahan maintains that he never “laid a hand on” his former wife.

“After having been confirmed for Deputy Secretary less than two years ago, it is unfortunate that a painful and deeply personal family situation from long ago is being dredged up and painted in an incomplete and therefore misleading way,” Shanahan said in a statement Tuesday. “I believe my continuing in the confirmation process would force my three children to relive a traumatic chapter in our family's life.”

In the case of high level appointees like secretary of defense, FBI investigators are able to marshal more resources for a more detailed background check than most civil servants would normally get. “They do up to about 40 face-to-face interviews,” said John Berry, an attorney who represents clients in security clearance cases, said. “A normal person with a top secret clearance, they may come and talk to like five or ten folks.”

Attorneys say that, absent any more revelations about Shanahan, the domestic violence allegations against his wife and son would probably not have stopped most applicants from getting a clearance, assuming investigators knew about them.

“The reason this probably slipped through is because, as far as I can tell, Shanahan was never charged with anything. So nothing would’ve popped up in a national criminal database check,” said Brad Moss, a national security lawyer with extensive experience handling clearance cases.

Shanahan’s resignation comes at a particularly fraught time for the Defense Department. Officials there are in the midst of dealing with increasing escalations with Tehran, and on Monday the administration announced that it was prepared to send an additional 1,000 troops to the Middle East to counter Iran’s presence in the region. Amid the absence of a confirmed secretary, the State Department has lead the way on Iran policy, crafting the maximum pressure campaign along with Treasury that’s led to more than a thousand sanctions designations against the country. State has also held briefings with Congress about Iran over the last several weeks.

While Tuesday’s revelations caught many lawmakers by surprise, others said they had been made aware of them before they were reported publicly.

“I know he’s been accused of things for a long time… he also is, keep in mind, he went to confirmation as the deputy. So that’s a process,” said Sen. Jim Inhofe (R-OK), the chairman of the Senate Armed Services Committee.

A senior White House official told The Daily Beast that Shanahan’s withdrawal has been expected for “a couple weeks” in light of the incidents, reports of which had been circulating internally.

“One concern was it would turn into another Kavanaugh situation,” the official said, referring to the highly contentious confirmation fight over the Supreme Court Justice. The White House anticipated that Senate Democrats might seize on reports of domestic problems in Shanahan’s home to attempt to tie him to the larger problem of domestic violence in the military.

Of particular concern, the White House official said, was Sen. Kirsten Gillibrand (D-N.Y.), a member of the Armed Services Committee, Democratic presidential candidate, and longtime critic of the Pentagon’s handling of sexual assault and abuse cases against female service members. Though not directly analogous to the litany of documented cases of such assaults, reports about Shanahan’s private life, the White House worried, might hand Gillibrand and like-minded committee Democrats a cudgel to wield against Shanahan’s nomination.

Shanahan’s replacement, Mark Esper, is currently the secretary of the Army and has a long history of working in top positions in the military and with government contractors, including Raytheon. Those who’ve known Esper over the years say he has the attitude of an entrenched bureaucrat who is eager to please his bosses.

“He was one of the top five guys in our class and he is highly regarded in the Trump administration,” said one former senior Pentagon official who attended school with Esper. Esper was also a classmate of Secretary of State Mike Pompeo at the U.S. Military Academy at West Point in 1986.

“He is very good at figuring out what his superior wants and he delivers,” the former official said. “And Mark’s approach to his work is to focus on the core mission in front of him—to prevail against the U.S.’s competitors. And he knows in this case those rivals are Russia and China.”

—with reporting by Adam Rawnsley