Van der zwaan is scheduled to be sentenced Tuesday in Washington at 10 a.m. ET in the first case in Mueller's investigation to reach that stage.
A veteran Republican strategist on Sunday warned that "a storm is coming" for Donald Trump and that it's "hard" to believe the special counsel investigation won't dig up "something" illicit in the president's long financial history.
Van der Zwaan was given the first sentence in Mueller's investigation into Russian meddling and potential collusion with Trump campaign associates during the 2016 presidential election.
Under federal sentencing guidelines, Van der Zwaan had faced zero to six months in prison.
This is a developing story. Gates and Manafort were working for Tymoshenko's political rival Victor Yanukovych at the time.
Mueller, in a sentencing memorandum issued last week, said "the government does not take a position with respect to a particular sentence to be imposed" on van der Zwaan.
Gates, 45, was indicted by a federal grand jury in October on eight counts, including fraud and money laundering, as part of the special counsel's probe into ties between the Trump campaign and the Russian government. Mueller has described Person A as having "ties to the Russian intelligence service".
Andrew Weissman, an attorney for the special counsel, argued for jail time and pushed back against van der Zwaan's request for leniency.
Mueller's prosecutors countered, asserting that van der Zwaan would be out of jail before his child's birth. Van der Zwaan later returned to the special counsel's office on December 1 to "correct the record", his lawyers wrote.
U.S. District Court Judge Amy Berman Jackson handed down the sentence in federal court in Washington, D.C.