W. Samuel Patten leaves a D.C. courtroom in August after pleading guilty to failing to register in the United States as a foreign agent. (Win McNamee/Getty Images)

An American political consultant who admitted steering $50,000 from a pro-Russian Ukrainian politician to Donald Trump’s inaugural committee cooperated with federal prosecutors on several matters that remain under seal and should receive leniency at sentencing, U.S. government attorneys argued Monday.

W. Samuel Patten, 47, faces sentencing Friday for failing to register as a foreign lobbyist while working on behalf of a Russia-aligned Ukrainian political party. He said that while he was helped in arranging the inaugural donation by a Russian national who is a longtime associate of former Trump campaign chairman Paul Manafort, he had no idea the associate had been linked to Russian intelligence by the FBI.

The charge in Patten’s case carries a maximum sentence of five years in prison.

His attorney, also citing his cooperation with special counsel Robert S. Mueller III’s Russia probe and other prosecutors, asked for probation and community service as each side presented sentencing memos.

Patten admitted in court documents that he arranged for an American citizen to act as a “straw donor” to give the $50,000 in exchange for four Trump inauguration tickets for a Ukrainian businessman who as a foreigner was barred from contributing to the event.

Trump’s inauguration was attended by an unusually large number of prominent foreign business leaders, particularly Russian moguls whose presence drew the attention of the FBI at the time.

Patten’s Aug. 31 guilty plea marked the first public confirmation that illegal foreign money was used to help fund Trump’s inaugural committee, which raised more than $100 million.

Federal prosecutors said no sentencing range in federal guidelines is directly applicable to Patten’s offense and did not cite a specific prison term in their recommendation, which has been their practice in cases that originated with Mueller’s probe of Russian interference in the 2016 presidential election.

However, the government filed a letter seeking leniency “because of Patten’s cooperation and the substantial assistance he has provided to the government.”

Patten’s case was referred to prosecutors with the U.S. attorney’s office in Washington and the Justice Department’s national security division by the special counsel. In a plea agreement, Patten agreed to cooperate with prosecutors.

Since then, the Trump committee and top officials have received subpoenas or requests for documents related to donations and spending from federal prosecutors in Manhattan, the attorneys general for the District and New Jersey, and the House Intelligence and Judiciary committees.

“Mr. Patten admitted his offenses and took full responsibility for his actions,” Patten attorney Stuart A. Sears wrote.

Patten “earned the trust of the government and became a reliable and valuable resource” for Mueller’s Russia investigation and prosecutors with the U.S. attorney’s office “in relation to several ongoing investigations,” Sears said. His help on those fronts remains under seal.

Patten has been released on his own recognizance pending sentencing before U.S. District Judge Amy Berman Jackson of Washington.

In plea papers, Patten also acknowledged he formed a company with a Russian national, identified only as “Foreigner A,” to engage in lobbying and political consulting services.

The company had received about $1 million since 2015 for its Ukraine consulting work, which included advising a Ukrainian party known as the Opposition Bloc as well as some of its members, one of whom is a prominent Ukrainian business executive identified only as “Foreigner B.”

Prosecutors said Patten helped the business executive get meetings to lobby members of Congress in 2015 and helped him author an op-ed in February 2017 that appears to match a U.S. News & World Report article arguing Ukraine would do fine under President Trump.

The description of “Foreigner A” matches Konstantin Kilimnik, a longtime Manafort associate who has been charged in Washington along with Manafort with obstruction of justice and witness tampering. Prosecutors have said they believe that Kilimnik has ties to Russian intelligence. Kilimnik has denied any such ties.

The description of “Foreigner B” matches Serhiy Lovochkin, a Ukrainian business executive and politician who served as a top aide to former Ukrainian president Viktor Yanukovych, a pro-Russian politician who was Manafort’s chief client.

Patten told prosecutors that he worked with Kilimnik to help Lovochkin route the illegal donation to Trump’s inauguration. As a result of the donation, four tickets to Trump’s festivities were allocated to the three men and another Ukrainian; prosecutors said Lovochkin attended the event with Patten. Prosecutors do not say whether Kilimnik attended.

Patten also agreed that he misled the Senate Intelligence Committee when he testified before the panel in January.

Kilimnik did not respond to a request for comment from The Washington Post. Lovochkin’s office said he attended the inauguration but didn’t make the $50,000 payment.

To the extent it mattered, his attorney argued, Patten opposed Trump’s candidacy, voted for his opponent in 2016 and volunteered his services in Alabama to help swing a 2017 special Senate election against Republican candidate Roy Moore.

Patten had no political agenda in the “wrongheaded effort” to purchase inauguration tickets other than being “blinded by a desire to accommodate his client,” Sears said.

Patten acknowledged to the Senate Intelligence Committee that he falsely minimized his contact with U.S. officials on behalf of foreign clients and manually deleted 200,000 emails from his Gmail archive folder, his attorney said. But he voluntarily provided materials that incriminated him, including over 1,300 pages of documents, Sears wrote.

“Regrettably, although Mr. Patten believed he had fulfilled his obligations to the Committee, he did not consult with his previous attorney or the Committee prior to the deletion of his archived emails,” Sears said. “He understands now that he should not have done so without, at a minimum, the Committee’s approval.”

Patten initially responded to the committee without receiving a subpoena and without consulting a lawyer, Sears said.

U.S. Attorney General William P. Barr announced that Mueller concluded his probe March 27 without further indictments, but the special counsel had been referring several matters to other prosecutors, including the U.S. attorney’s office for the District.

Patten has a varied résumé. He worked in the oil sector in Kazakhstan in the mid- to late 1990s and served as Maine campaign director for George W. Bush’s 2000 presidential run. He also briefly worked at the State Department under Bush and as a political consultant in Iraq assisting officials there in the post-Saddam Hussein period.

In a 2017 interview with The Post, Patten said he met Kilimnik in Moscow more than 15 years ago, when Kilimnik was an employee of the International Republican Institute, a pro-democracy group affiliated with the U.S. Republican Party. Patten ran the office from 2001 to 2004. “I relied on him,” Patten told The Post.

Kilimnik left the IRI around 2005 to work for Manafort in Kiev, the Ukrainian capital, starting as the American consultant’s interpreter and eventually being named manager of Manafort’s Ukraine office. Patten praised Kilimnik at the time as a person who helped Manafort navigate the complicated Ukrainian political scene.

In 2015, Patten and Kilimnik jointly formed a company incorporated in Washington called Begemot Ventures International. Begemot, which means “hippopotamus” in Russian, is the name of the mischievous cat who pals around with the Devil in the celebrated Russian novel “The Master and Margarita.”

Patten was born into a milieu of social climbing and Washington power politics. He is a grandson of the late Georgetown doyenne Susan Mary Alsop.

Patten’s father moved to Maine, ran a small-town weekly newspaper and later became a prison minister. Patten was schooled in Maine and attended Georgetown University, graduating in 1993.