An array of critics of acting Attorney General Matthew Whitaker are using legal machinery to challenge him on multiple fronts, from the constitutionality of his appointment by President Trump, to the secrecy around his financial disclosure forms, to his refusal to recuse himself from decisions affecting Special Counsel Robert Mueller’s probe of Russian meddling in the 2016 U.S. elections.

On Monday, three Democratic senators filed a lawsuit in U.S. District Court for the District of Columbia saying the Nov. 7 appointment of Whitaker following Trump’s firing of Attorney General Jeff Sessions violates the Constitution’s Appointments Clause because Whitaker, in serving as a principal federal officer, has never been confirmed by the Senate.

“Installing Matthew Whitaker so flagrantly defies constitutional law that any viewer of School House Rock would recognize it,” said Sen. Richard Blumenthal, D-Conn., who filed the suit with Sens. Mazie Hirono, D-Hawaii, and Sheldon Whitehouse, D-R.I.  “President Trump is denying Senators our constitutional obligation and opportunity to do our job: scrutinizing the nomination of our nation’s top law enforcement official. The reason is simple: Whitaker would never pass the advice and consent test. In selecting a so-called ‘constitutional nobody’ and thwarting every Senator’s constitutional duty, Trump leaves us no choice but to seek recourse through the courts.”

The senators’ case follows similar action by state and local officials in Maryland and California. The senators are being legally represented by the nonprofit firms Protect Democracy and the Constitutional Accountability Center.

“The prospect that the attorney general might seek to serve the president, rather than the American people, reaffirms the importance of a confirmation process that follows the Constitution,” said Anne Tindall, counsel at Protect Democracy.

The White House has argued that the president is permitted to make such temporary appointments under the 1998 Federal Vacancies Reform Act.

Over the weekend, a controversy also broke out over Whitaker’s financial disclosure forms. The nonprofit transparency group American Oversight wrote to Office of Government Ethics Director Emory Rounds protesting the fact that the Justice Department has not released the disclosure forms 278e and 278-T, even though Whitaker has been at the Justice Department as chief of staff since Oct. 4, 2017.

“Appointees to senior government positions covered by this filing requirement must file their public financial disclosures within 30 days of assuming the duties of the position covered by the filing requirements,” with a copy to Justice Department ethics office director Cynthia Shaw, wrote American Oversight Executive Director Austin Evers. “The appointee’s agency may grant an extension of up to 45 days for good cause shown, with the possibility of an additional extension of up to 45 days.”

Consequently, the group argued, the latest possible deadline for the department to release Whitaker’s disclosures was Feb. 1, 2018. “The Department of Justice has not yet permitted inspection or furnished a copy of these public financial disclosure reports, notwithstanding the overwhelming public interest in understanding the potential conflicts of interest of the new Acting Attorney General,” Evers continued.

The letter urges an OGE investigation of Justice’s “apparent unwillingness to make his public financial disclosure reports publicly available or even provide an estimate for disclosure.” The secrecy, it continued, “also raises the disturbing possibility that Mr. Whitaker has potentially failed to comply with his legal obligations under OGE regulations to file timely public disclosures.”

Cheering on the American Oversight move via Twitter was former OGE Director Walter Shaub, now with the nonprofit Citizens for Responsibility and Ethics in Washington. “This is an outrage,” Shaub tweeted over the weekend. “DOJ’s refusing to release Whitaker’s financial disclosure form is illegal, unheard of, and highly suspicious. What is DOJ hiding?”

His own group, CREW, meanwhile, on Nov. 14 wrote to assistant Attorney General Lee Lofthus of Justice’s management division reiterating a previous request that Whitaker recuse himself from decision on the ongoing Mueller probe.

It mentions “possible coordination between the Russian government and individuals associated with the campaign of President Trump, and the investigation by the U.S. Attorney for the Southern District of New York into personal income tax, false statement, campaign finance, and other offenses involving [previous Trump personal attorney] Michael Cohen, the Trump Organization and the Trump Campaign.”

The reason for the second letter, said CREW Executive Director Noah Bookbinder and Chairman Norm Eisen, was the recent emergence of several news stories about comments or actions of Whitaker before Trump named him as acting attorney general. Whitaker’s uncovered statements on television shows expressing skepticism on the validity of the Mueller probe, his past work with a Florida company investigated for fraud by the FBI and Federal Trade Commission, and a possible conflict-of-interest in Whitaker’s relationship with Sam Clovis, a former co-chair of the Trump Campaign, all struck the CREW leaders as “troubling.”

The Justice Department did not respond to Government Executive requests for comment.