Prosecutors with the U.S. Attorney's Office for the Southern District of New York asked U.S. District Judge William Pauley III Friday to sentence Michael Cohen, President Donald Trump's former personal lawyer, to a “substantial term of imprisonment,” to be tempered only slightly by Cohen's willingness to talk to members of the Special Counsel Robert Mueller III's team.

In their sentencing submission, prosecutors from Manhattan U.S. Attorney Geoffrey Berman's office acknowledged Cohen's help, but strongly urged the court not to mistake Cohen's efforts for those of a traditional cooperator. The document was signed by Deputy U.S. Attorney Robert Khuzami, who is piloting the case for the Southern District as Berman recused himself from the matter.

Read the memo:

“Cohen did provide information to law enforcement, including information that assisted the Special Counsel's Office … in ongoing matters, as described in the SCO's memorandum to  the Court, and the Office agrees that this is a factor to be considered by the Court pursuant,” Assistant U.S. Attorney Nicole Roos wrote for the government. “But Cohen's description of those efforts is  overstated in some respects and incomplete in others.”

The government noted that sentencing guidelines for the eight counts he pleaded guilty to in the Southern District earlier this year, including campaign finance violations, suggested a sentence of 51 to 63 months in prison. In a footnote, the memo said the U.S. Probation Office recommended a term of 42 months.

“This range reflects Cohen's extensive, deliberate, and serious criminal conduct, and this Office submits that a substantial prison term is required to vindicate the purposes and principles of sentencing,” Roos wrote. “And while the Office agrees that Cohen should receive credit for his assistance in the SCO investigation, that credit should not approximate the credit a traditional cooperating witness would receive, given, among other reasons, Cohen's affirmative decision not to become one.”

In a separate filing, attorneys with Mueller's office struck a decidedly softer tone. Nothing Cohen's cooperative efforts, noting that despite the severity of his crime of lying to Congress, Cohen “has taken significant steps to mitigate his criminal conduct.”

“Cohen's decision not only to admit to his prior false statements in proffer sessions with the Government, but to plead guilty to his criminal conduct in open court, demonstrates that Cohen has taken responsibility for his wrongdoing and is willing to face the consequences,” prosecutor's with the Special Counsel's office said in its filing.

A spokesman for Cohen provided no comment on the record when asked.

Both Manhattan and Special Counsel prosecutors were ordered to file their sentencing memos by 5 p.m. Friday. Cohen's sentencing is scheduled for Dec. 12, on two separate guilty pleas he entered into in recent months.

Cohen's plea dealing began back in April, when federal agents in New York executed a search warrant on Cohen's offices and home. The president's former attorney initially took an adversarial stance towards the government's investigations. Cohen and his attorneys with McDermott, Will & Emery quickly fought to keep federal investigators in Manhattan from having direct access to the seized goods. Instead, U.S. District Judge Kimba Wood oversaw a months-long privilege review process overseen by Bracewell partner and former federal judge Barbara Jones.

The process, which involves attorneys for the president and the Trump Organization, ultimately resulted in the vast majority of the material seized being turned over the government. As the process unfolded, Cohen's tune began to change. First in media reports and later during an interview with ABC News, Cohen indicated his priorities were shifting away from the sentiment that he'd take a bullet for Trump.

Around the same time, Cohen was changing legal teams—and strategies. The attorneys at McDermott departed, and Petrillo Klein & Boxer name attorney Guy Petrillo, a former federal prosecutor in Manhattan, took over.

Soon, Cohen was meeting with federal prosecutors connected with the Special Counsel's office, according to Cohen's Dec. 5 sentencing filing. Before entering into his first plea, Cohen met seven times with SCO personnel, according to the filing.

On Aug. 21, Cohen pleaded guilty to eight counts, including tax evasion and federal campaign finance violations. The court documents detail Cohen's efforts to silence two women through pay-off schemes, to keep their stories about extra-marital sexual affairs with Trump from going public. The then-presidential candidate is heavily inculpated throughout the filings.

In late November, Cohen was back in court with another plea. This time, the president's former attorney and fixer pleaded guilty to a single count of lying to Congress about the status of plans to build a Trump-branded building in Moscow in the midst of the 2016 presidential election. According to Cohen's sentencing submission, discussions about his second plea began even before the first occurred, during those seven conversations with the SCO “based in part on information that he voluntarily provided … in meetings governed by a limited-use immunity proffer agreement.”

Cohen argued that his substantial cooperation, with both federal and New York State authorities, and his willingness to do so should save him from facing time behind bars.