Special Counsel Robert Mueller is recommending Michael Flynn, President Trump’s short-lived national security adviser, serve no jail time for lying to the feds about his contact with Russian officials and work on behalf of Turkish ones.

In memo filed Tuesday night, prosecutors cited Flynn’s “exemplary” military service and his cooperation in the case in suggesting he get the “low end” of a possible six-month sentence—“including a sentence that does not impose a term of incarceration”—on Dec. 18.

They outlined Flynn’s cooperation in a document that was heavily redacted but nonetheless revealed he assisted with the investigation “on a range of issues, including interactions between individuals in the Presidential Transition Team and Russia.”

It noted that Flynn has “provided firsthand information about the content and context of interactions between the transition team and Russian government officials.” And it stressed that his “early cooperation” probably spurred other “firsthand witnesses” to cooperate.

After Flynn began assisting with the the special counsel's office, prosecutors were able to rack up a number of other cooperating witnesses. Among those witnesses are George Nader, who reportedly provided information about a meeting between Trump campaign adviser Erik Prince and Russia's sovereign wealth fund chief during the transition, and a former Trump campaign staffer who served as the star witness at former campaign chairman Paul Manafort's bank and tax fraud trial.

Mueller's leniency toward Flynn stands in stark contrast to the hard line he took with former Trump campaign chief Paul Manafort, whose plea agreement is in jeopardy because investigators say that he lied to them after cutting a deal to cooperate.

Flynn conducted over 19 separate interviews with prosecutors over the course of his cooperation with Mueller's team, according to the sentencing recommendation filing Tuesday evening, and turned over several "documents and communications." The former White House national security adviser's help appears to have touched on at least two "ongoing investigations" referred to in the memo: the Russia investigation, an unspecified criminal investigation, and what may be a third, redacted line of inquiry.

Flynn pleaded guilty in December 2017 to one count of lying to federal investigators about his conversations with Russian officials a year earlier.

During a January 2017 FBI interview, Flynn denied asking Russian ambassador Sergey Kislyak to “refrain from escalating” after President Obama sanctioned Russia for its alleged election-meddling. Flynn also admitted to lying about asking Kislyak to delay voting on a U.N. Security Council resolution condemning Israeli settlements.

In a statement released after his December plea, Flynn said it had been “extraordinarily painful to endure these many months of false accusations of ‘treason’ and other outrageous acts.” Nonetheless, he said, he recognized “that the actions I acknowledged in court today were wrong, and, through my faith in God, I am working to set things right.”

The special counsel’s office also noted that Flynn lied about his work on behalf of the Turkish government in lobbying registration paperwork, but declined to charge him under the Foreign Agents Registration Act. Flynn signed a $600,000 lobbying contact with Turkish businessman Ekim Alptekin and, according to prosecutors, failed to disclose that he knew the lobbying work was ultimately directed by the Turkish government.

Prosecutors also investigated Flynn’s role in an alleged plot to kidnap an expat Turkish cleric. The Wall Street Journal reported that Flynn allegedly met with Turkish officials in December 2016 and discussed a $15 million plan to kidnap exiled Turkish dissident Fethullah Gulen from his home in Pennsylvania for prosecution in Turkey.

In an amended lobbying registration filed in 2017, Flynn also disclosed that he had visited Egypt and Israel to lobby on behalf of a Saudi-funded project to build nuclear power plants in the Middle East. The plan, floated by X-Co Dynamics Inc./Iron Bridge Group based in Washington, D.C., called for the U.S. and Russian to provide the nuclear technology and waste disposal.

Flynn’s friendliness with Russian officials became an issue during the 2016 campaign after he accepted a paid trip Moscow and sat next to Russian President Vladimir Putin during a gala dinner for the state-run RT propaganda channel. The Defense Intelligence Agency subsequently acknowledged that Flynn had not disclosed the trip or the $33,000 RT had paid him for his appearance when he applied for a security clearance renewal.

Flynn remains the highest-ranking member of both the Trump campaign and the Trump administration to be indicted in connection with the Russia investigation. He resigned as national security adviser in Feb 23 after less than a month on the job, making him the shortest-serving national security adviser in the nearly 70-year history of the position.

The plea agreement notes that Flynn could face a sentence of up to six months in prison and a fine of $9,500. Defendants facing similar charges from the special counsel’s office have received much smaller sentences after cooperating with prosecutors. Flynn is scheduled to be sentenced on Dec. 18.