A recent Russian demand that the United States secure the release of Vadim Krasikov, a Russian assassin serving a life sentence for murder in Germany, was deemed a non-starter.
To some of Mr. Whelan’s supporters, it feels as though the cards most likely to win his freedom have been played.
“I’m pretty up to speed with Russians in U.S. jails, and I don’t think there are any accused of any espionage-type of crime” that the Kremlin would consider equivalent to trade for Mr. Whelan, said his lawyer, Ryan Fayhee, a former national security official with the Justice Department.
“We need to arrest a Russian that matters to” President Vladimir V. Putin, Mr. Sipher said.
As it happens, the Justice Department announced the indictment of five Russian nationals on Tuesday on charges of money laundering and procuring electronics and ammunition for Moscow’s war machine despite sanctions. The Justice Department said in a statement that one them, Vadim Konoshchenok, is a suspected member of the Federal Security Service, or F.S.B. He was arrested in Estonia, a close U.S. ally, and will be extradited to the United States, the department said. The other four remain at large.
Neither name has publicly surfaced in connection with Mr. Whelan’s case.
It may be that Mr. Whelan could be freed by means other than a prisoner exchange. U.S. officials have ruled out relaxing sanctions imposed on Russia for invading Ukraine. But the United States also enacted many other Russian sanctions in the years before the invasion, and the White House official would not say whether those were off the table.
While Mr. Whelan’s family members and supporters do not begrudge the freedom of Ms Griner or Mr. Reed — whose release became an urgent priority for the White House amid concerns about his health — they find the difficulty in freeing Mr. Whelan to be maddening.
“Out of the group, he was the first one arrested,” said Rep. Haley Stevens, Democrat of Michigan, who represents Mr. Whelan’s district. “And he’s been the longest detained.”
Julian E. Barnes contributed reporting.