Washington CNN  — 

The Justice Department has closed its year-old criminal investigation into former Trump national security adviser John Bolton and dropped a related lawsuit connected to the publication of his book about the ex-President’s diplomatic bungling.

The Trump-era criminal investigation had scrutinized whether Bolton’s book illegally revealed national security information, while the lawsuit had sought to grab royalties from Bolton for publishing his book without the administration’s full approval.

The end of the proceedings marks yet another wrap-up by the Biden administration of politically charged cases and investigative moves toward Trump’s political opponents. In recent weeks, the Justice Department has dropped or changed their approach to several matters the Trump-era department had pursued, and announced its now-Deputy Attorney General Lisa Monaco is looking into “potentially problematic matters” in addition to policies that the new administration may want to change.

The Justice Department dropping the cases comes on the one-year anniversary of the emergency lawsuit against Bolton.

Bolton told CNN’s Wolf Blitzer on “The Situation Room” on Wednesday that his book “did go through a pre-publication review process” and that it “was cleared by the expert team that reviewed it, arduously.”

“Look, I think this was a vindication of the view that I’ve had from the beginning that Trump used the question of classified information purely as a pretext to try and suppress a book he did not want to come out before the November 2020 election,” he said of the cases being dropped.

Pressed on whether he thought the legal proceedings were an exercise in retribution, Bolton said, “As is the case with almost everything involving Trump, it was all about Trump and his political fortunes.”

Bolton’s attorney Charles Cooper applauded President Joe Biden’s Justice Department for ending all of the legal proceedings against the Trump adviser-turned-political foe. Cooper said the cases appeared to be politically motivated.

“We argued from the outset that neither action was justifiable, because they were initiated only as a result of President Trump’s politically motivated order to prevent publication of the Ambassador’s book before the 2020 election,” Cooper said in a statement.

“By ending these proceedings without in any way penalizing Ambassador Bolton or limiting his proceeds from the book, the Department of Justice has tacitly acknowledged that President Trump and his White House officials acted illegitimately,” Cooper added.

The book, released in June 2020, boasted a series of shocking allegations, including that Trump requested Chinese help to win the 2020 presidential election, had argued Venezuela is part of the US, had casually offered to intervene in the criminal justice system for foreign leaders, and that his own senior officials mocked him behind his back.

Early in the Biden administration, Justice Department officials began discussing ways to end the criminal investigation of Bolton, according to people briefed on the matter.

Career lawyers had long viewed the civil and criminal cases as politically tainted because of the involvement of top White House officials and the former president’s public statements.

Prosecutors also realized, the people briefed on the matter said, that they likely couldn’t use testimony from what would have been their star witness, Michael Ellis, a former White House national security lawyer who played a role in retroactively classifying parts of Bolton’s book and whom the former president tried to install as general counsel at the National Security Agency. The Biden administration suspended the NSA appointment and it became the subject of an internal Pentagon probe before he eventually resigned.

The Bolton book – a damaging moment for Trump politically during an election year – is one of the episodes that garnered significant criticism of the Trump administration’s politicization of the intelligence community and Justice Department.

Trump-era effort to stop the book

Former Attorney General William Barr had signed off on a White House request to sue in order to stop the publication of Bolton’s book in an extraordinary move just days before its release.

In line with his hands-off approach outside of his political circle, Barr sent then-Deputy Attorney General Jeffrey Rosen to discuss with department attorneys how they must file the lawsuit against Bolton, a person familiar with the handling of the case previously told CNN.

The lawyers advised that an attempt to stop the book publication was ill-fated. But their concerns were ignored and Barr signed off on the lawsuit, the person said. That part of the lawsuit, seeking to stop the publication, failed because the book was already in booksellers’ hands.

Earlier this year, a federal judge ruled that Bolton could seek evidence about the classification process around his book in case there was bad faith decision-making by the White House and intelligence community meant to protect Trump politically.

That decision had put the Justice Department in a potentially difficult spot, as the door had opened for Bolton’s legal team to push to interview under oath people around the President.

A long-time government official specializing in classification had stepped forward last fall to allege the Trump White House mishandled classification around the book, and said she believed she had been forced out of a job because of the then-President’s ire toward Bolton.

The lawyer, Ellen Knight, wondered “how it could be appropriate that a designedly apolitical process had been commandeered by political appointees for a seemingly political purpose,” her attorneys wrote about her work reviewing Bolton’s manuscript, which she largely approved for publication before lawyers close to Trump stepped in, blocking sign-off.

Generally, if a writer who worked for the government doesn’t get full approval before a book’s publication, the Justice Department is able to sue after the fact to attempt to collect the writer’s earnings.

Bolton stood to lose millions in this case.

The DOJ in court for the lawsuit had made known that the Trump administration was also investigating him for criminal violations.

This story has been updated with additional details.