They allege Papadopoulos thwarted an ongoing national security investigation and contributed to them losing track of Joseph Mifsud, the professor who knew about the "dirt" on Hillary Clinton, before they could effectively question him.
Federal prosecutors with the special counsel's office had asked Judge Randolph Moss for a sentence of up to six months in prison.
Papadopoulos lied because he was torn between wanting to cooperate and wanting to remain loyal to a president whose administration he hoped to join, Breen said.
"Judge said he believed Papadopoulos was genuinely remorseful but didn't agree to a probation sentence because he needed to send a message about the seriousness of lying to the FBI", Cheney wrote in a subsequent tweet.
"We are very satisfied with the sentence", Papadopoulos's lawyer, Thomas Breen, told reporters after the hearing.
Far from cooperating to energize the special counsel probe, prosecutors Jeannie Rhee, Andrew Goldstein and Aaron Zelinsky argued, Papadopoulos and his wife gave life to a false narrative about them and the seriousness of his offense.
"People point and snicker and I am terribly depressed", he said.
"Mr. Papadopoulos's offense was unquestionably serious as he made materially false statements to Federal Bureau of Investigation agents", they wrote in their sentencing memo.
The FBI met with Mifsud while he was visiting the United States in early 2017, but Papadopoulos' lies "undermined investigators' ability to challenge the professor or potentially detain or arrest him".
Tropical Storm Gordon Sets Sights on Mississippi
Mayors of barrier islands in the storm's path warned that their communities might get cut off from the mainland. The tropical storm continues to approach the Gulf Coast.
He has cooperated for more than a year with the probe into Russian interference in the United States presidential election, and possible collusion with the Trump campaign. With his constant cries of "fake news", Trump has "hindered this investigation more than George Papadopoulos ever did", Breen said.
"My recollection was that the senator [Jeff Sessions] was actually enthusiastic about a meeting between the candidate and President Putin". The case was kept under seal for three weeks after his guilty plea and made public only when Mueller announced the indictments of campaign chairman Paul Manafort and his top deputy, Rick Gates, for money laundering, illegal lobbying and other charges unrelated to the election. "This investigation has global implications and the truth matters".
Sessions has previously testified to Congress that he pushed back against the proposal, but the memo filed by Papadopoulos's lawyers contradicts Sessions' account, saying that both Trump and Sessions appeared receptive to the idea.
After Papadopoulos and his legal team left the courthouse in a black Chevy Suburban, his family members hung behind outside the courthouse.
That clashes with what Sessions, a key campaign aide and now Trump's attorney general, told the House Judiciary Committee last November.
Papadopoulos, who served as a foreign policy adviser to Trump's campaign, has been a central figure in the Russian Federation investigation dating back before Mueller's May 2017 appointment.
"We don't talk politics", he said.
Papadopoulos also made a similar claim about Sessions last week in court.