WASHINGTON (NewsNation Now) — U.S. President Donald Trump tweeted Wednesday he has pardoned his former national security adviser Michael Flynn, who had pleaded guilty to lying to the FBI during an investigation into Russian meddling in the 2016 presidential election.

“It is my Great Honor to announce that General Michael T. Flynn has been granted a Full Pardon,” Trump tweeted. “Congratulations to @GenFlynn and his wonderful family, I know you will now have a truly fantastic Thanksgiving!”

Flynn is the second Trump associate convicted in the Russia probe to be granted clemency by the president. Trump commuted the sentence of longtime confidant Roger Stone just days before he was to report to prison. A Pew Research Center report shows Trump has granted clemency less frequently than any other president in modern history.

Flynn, a retired Army general, pleaded guilty in 2017 to lying to the FBI about interactions he had with Russia’s ambassador to the United States in the weeks before Trump took office. He has since sought to withdraw the plea, arguing prosecutors violated his rights and duped him into a plea agreement.

The action voids the criminal case against Flynn just as a federal judge was weighing whether to grant a Justice Department request to dismiss the prosecution despite Flynn’s own guilty plea to lying to the FBI about his Russia contacts.

The pardon is the final step after the Justice Department abruptly moved to dismiss the case, insisting that Flynn should have never been interviewed by the FBI in the first place, only to have U.S. District Justice Emmet Sullivan refuse the request and appoint a former judge to argue against the federal government’s position.

In the months since, a three-judge panel’s decision ordering Sullivan to dismiss the case was overturned by the full appeals court, which sent the matter back to Sullivan. At a hearing in September, Flynn lawyer Sidney Powell told the judge that she had discussed the Flynn case with Trump but also said she did not want a pardon — presumably because she wanted him to be vindicated in the courts.

The pardon spares Flynn the possibility of any prison sentence, which Sullivan could potentially have imposed had he ultimately decided to reject the Justice Department’s dismissal request. That request was made in May after a review of the case by a federal prosecutor from St. Louis who had been specially appointed by Attorney General William Barr.

Democrat Joe Biden defeated Trump in the presidential elections earlier this month, but Trump has refused to formally concede, alleging without evidence that there was widespread voter fraud. However, Trump on Monday gave the go-ahead for federal funds to start flowing to Biden so he can carry out his transition duties before his Jan. 20 inauguration.

Flynn was one of several former Trump aides to plead guilty or be convicted at trial in former Special Counsel Robert Mueller’s investigation into Moscow’s interference in the 2016 U.S. election to boost Trump’s candidacy.

Trump in March said he was strongly considering a full pardon for Flynn. He said the FBI and Justice Department had “destroyed” Flynn’s life and that of his family. 

NewsNation’s Rob Nelson spoke to presidential historian Robert Dallek about the pardon; watch the interview below:

The Associated Press and Reuters contributed to this report