On March 2, former Acting Attorney General Matthew Whitaker abruptly resigned from a new Justice Department position only two weeks into the job—after he learned that he would likely be fired if he refused to answer questions from the department’s Inspector General about his controversial tenure as the nation’s top law enforcement official.

As a result, investigators may never learn whether President Trump attempted to enlist Whitaker in an effort to impede a federal criminal investigation into whether the president himself conspired to violate campaign finance laws. And Whitaker most likely will no longer be compelled to answer questions on a wide variety of other issues by investigators for the Justice Department he once headed. The department’s Inspector General has no authority to subpoena or require testimony from former officials, whereas those who still work for the department are subject to severe disciplinary measures if they refuse to cooperate with investigators, most often resulting in their immediate dismissal. By resigning, Whitaker most likely will have evaded the IG’s questioning.

The Inspector General is currently reviewing requests to the department from at least ten senators to investigate Whitaker’s conduct as acting attorney general. More than one of those have asked the IG to scrutinize conversations that Whitaker had with President Trump about the federal criminal investigation of the president by the office of United States Attorney for the Southern District of New York, which has been looking into whether hush money payments that Trump allegedly directed be paid in the closing days of the 2016 presidential election, to two women with whom he allegedly had extramarital affairs, were illegal campaign contributions. The senators want to know if Trump sought to impede or curtail either investigation, and whether Whitaker provided confidential information to the president about either one.

During a February 8 appearance before the House Judiciary Committee, Whitaker, citing executive privilege, refused to answer similar questions from members of Congress about his conversations with the president about the investigation of Trump by the SDNY. But at that hearing, Whitaker pledged to cooperate fully with any investigation by the Justice Department’s Inspector General. That promise now appears disingenuous in light of Whitaker’s resignation and his statements to others in the department that he resigned so that he would not have to submit to questioning by the IG. That Whitaker has refused to answer such questions from Congress and will likely do the same regarding the IG raises the possibility that he may never be formally questioned by any governmental investigative or oversight entity about his conversations with the president.

A senior Justice Department official in whom Whitaker confided about the matter told me that Whitaker expressed serious concerns over testifying about conversations that he had with the president about the SDNY’s investigation. Whitaker apparently did not understand that by taking a new job with the Justice Department, he could be required to discuss those conversations with the Inspector General. Whitaker, I was told, seemed relieved to learn that after he left the department, he likely could not be compelled to cooperate. Whitaker then sought out other Justice Department officials, this person told me, to determine whether there was any current investigation by the Inspector General at the time. Told that there was not one, but might be one soon, Whitaker resigned.

In one of Whitaker’s conversations (as acting attorney general) with the president, which Whitaker conveyed to others, Trump had questioned him as to whether the SDNY had been overzealous or unfair in its handling of Michael Cohen, a former executive vice president of the Trump Organization, the president’s personal attorney, and “fixer.” Whitaker’s account of that conversation may be crucial to investigators because the president also asked Whitaker if anything could be done to rein in the SDNY’s investigation.

According to testimony to Congress from both former FBI director James Comey and Cohen, it is clear that Trump habitually speaks in an indirect, elliptical way, disguising something that may be an instruction as an innocuous inquiry—in Cohen’s words, “He doesn’t give you questions, he doesn’t give you orders. He speaks in code, and I understand the code because I’ve been around him for a decade.” With the Mueller report leaving open-ended the question of whether the president obstructed justice, neither concluding “that the president committed a crime” nor exonerating him, Whitaker’s potential testimony on exactly how Trump framed his request about the SDNY investigation could be vital in determining whether the president engaged in an improper effort to impede that inquiry, possibly even to obstruct justice.

Judging by his subsequent conduct, Whitaker got the message. According to two officials with direct knowledge of the matter, not long after that conversation with the president, Whitaker had conversations with other senior Justice Department officials during which he questioned the legitimacy of the SDNY’s investigation. Cohen pleaded guilty in August of last year to arranging hush money payments in the weeks before the 2016 election. In pleading guilty, Cohen acknowledged that the payments were illegal campaign contributions and were made “in coordination with and at the direction of a candidate for federal office.”

In his conversations with other Justice Department officials, Whitaker noted that former senator John Edwards escaped federal criminal charges that he’d directed nearly $1 million to be paid to his pregnant mistress during the 2008 presidential campaign. After a lengthy trial, Edwards was found not guilty on one count and the jury deadlocked on five other felony charges. Embarrassed by this failure, the Justice Department chose not to retry Edwards.

In the same conversation, Whitaker also brought up the case of John Ensign, a former Republican senator from Nevada, who resigned in disgrace in 2011 after it was disclosed that he had directed his family to make $96,000 in hush money payments to the wife of a former aide, with whom Ensign had had a long-running extramarital affair. Ensign was investigated by the Justice Department, which believed that the payments to his mistress were illegal campaign contributions, and that Ensign might have obstructed justice to cover this up. An aide to Ensign, whose wife was the woman in question, pled guilty for his role in the scheme, but Ensign himself was never charged. Whitaker argued that the Ensign case was even more of a parallel to the SDNY’s investigation of the president than the Edwards case was, and that the SDNY’s efforts were thus even more dubious.

A person familiar with Whitaker’s conversation with colleagues at the Justice Department, in criticizing the SDNY’s investigation, said that Whitaker’s comments “weren’t just made in passing,” but rather that he was “well briefed… well prepared.” “Whitaker,” this official said, “was loaded for bear,” meaning that his arguments had firepower. Although Whitaker has stated that he never had any conversations with officials of the SDNY about their investigation, his conversations in the Justice Department in D.C. were with people who were superiors to the US Attorney of SDNY.

In a second instance in which Trump appeared to try to interfere with the SDNY’s investigation, first reported by The New York Times, the president asked Whitaker whether Geoffrey Berman, the US Attorney for the Southern District of New York who had originally recused himself from involvement in the investigation of the hush money payments, to reverse himself and take charge of it once again. Berman had contributed to Trump’s presidential campaign and had worked for his presidential transition team. Whitaker declined to follow up, knowing that Berman would never undo his own recusal at the request of one of the people under investigation—even the president of the United States.

The Times also reported that Whitaker told other senior DOJ officials in Washington that prosecutors and FBI agents working in the SDNY were in need of “adult supervision.” The comment had an unintended irony, since Whitaker knew only too well how the president liked to install loyalists in top senior law enforcement positions overseeing criminal investigations of Trump. Whitaker himself had scant credentials for acting attorney general when Trump appointed him after admiring Whitaker’s performances on cable television attacking the Mueller investigation. Once in post, reported the Times, Whitaker said he saw his job primarily as being willing to “jump on a grenade” for the president.

Whitaker’s stint as the acting attorney general ended on February 14, with the swearing in of William Barr. On that same day, Whitaker started work as senior counsel to the office of the associate attorney general, only to quit that position on March 2. The Office of the Associate Attorney General oversees the Justice Department’s Civil Rights Division, its Antitrust Division, Tax Division, Environment and Natural Resources Division, and various other offices. A person close to Whitaker told me that Whitaker understood that when he took the post it would only be for a short-term basis, but another official told me: “You don’t park someone in a job like that for two weeks.” Several of Whitaker’s other colleagues were puzzled by his hasty departure. Efforts to reach Whitaker for comment through the Justice Department and a nonprofit he once headed were unsuccessful.

It is standard practice for Justice Department officials to be fired if they refuse to cooperate with investigations by the agency’s Inspector General. Whitaker, though, would have been the highest-level official in the department’s history to be fired if he had stayed on but refused to answer questions from the IG. Whitaker was advised by department officials that, unlike the case of his appearance before the House Judiciary Committee, he would not be able to invoke executive privilege with the IG, because Whitaker and the IG, as employees of the Justice Department, both belonged to the executive branch.

Mark Rozell, dean of the Schar School of Policy and Government at George Mason University and the author of Executive Privilege: Presidential Power, Secrecy and Accountability (2010), explained to me that executive branch officials can only credibly attempt to assert executive privilege to withhold information or testimony from the judicial or legislative branch: “I don’t know of a single instance in which a president has asserted the claim within his own branch of government.” One of the Justice Department officials who spoke to me said that Whitaker was counseled: “It would not be legitimate assertion of executive privilege for the president to say that his own attorney general, or any other Justice Department official, should not provide information to the Department’s Inspector General.”

Whitaker is by no means the first senior Justice Department official to refuse to speak to investigators once they have left the department. In one incident, a senior Bush administration political appointee evaded both questioning and dismissal by resigning earlier the day she was due to be interviewed. Among other former senior officials who have refused to be interviewed by the IG after leaving the department have been the former attorney general John Ashcroft, who served for the first George W. Bush administration, and Chris Christie, who before he was the governor of New Jersey, had been the United States Attorney for the state.

In a small number of instances, the Inspector General has referred potential criminal misconduct by former or current DOJ officials for investigation by other offices within the Justice Department. Sometimes, former Justice Department officials have then been subpoenaed to answer questions before a federal grand jury. Relatively rare though this is, it may turn out to be the case with Whitaker—because the issue of whether the president of the United States attempted to impede or obstruct a federal criminal investigation is of such consequence.

If the Inspector General believes that a witness has misled or lied to investigators, he can recommend that the Justice Department commence a criminal investigation. Lying to an Inspector General is a felony. Whitaker expressed misgivings to one department official about answering questions that might be posed to him by investigators, telling the same official that he feared that even if he told the truth, the IG might search for any pretext to try to build a case against him. Whitaker said that he knew that many career DOJ officials disapproved of his close relationship with President Trump, and was aware of the perception that Trump appointed him to be the acting AG to limit or even impede special counsel Robert Mueller’s investigation.

The potential legal jeopardy of Whitaker’s testifying about his tenure as attorney general was underscored recently when the chairman of the House Judiciary Committee, Representative Jerrold Nadler, Democrat of New York, alleged that Whitaker may have given misleading testimony regarding his conversations with Trump about the investigations of the special counsel and SDNY prosecutors. The House Judiciary Committee’s inquiry continues, and Senate Democrats, too, may review their options now that Whitaker has put himself beyond reach of the Inspector General. As Mueller’s report does “not conclude that the president committed a crime,” though “it also does not exonerate him,” and with Barr declining to prosecute Trump, congressional Democrats may have further questions for Whitaker about his interactions with the president over the SDNY investigation.