Russian President Vladimir Putin’s preparation for a new invasion of Ukraine could hold dire consequences for U.S. citizen Paul Whelan, who has been imprisoned in Russia for nearly three years.

“Another Russian invasion of Ukraine — that illegal step would create profound problems for our ability to help Paul,” twin brother David Whelan told the Washington Examiner.

The third anniversary of Paul Whelan's detention falls on Dec. 28, the Christmas season’s dolorous day for his parents and siblings. He was convicted of espionage following a trial conducted in Russian (despite his ignorance of the language), but he has maintained throughout the controversy that he was framed by a Russian intelligence officer who planted a USB drive in his hotel room.

"That person was an FSB officer. He's someone I've known for 10 years," Paul Whelan said in court last year. ”There’s absolutely no reason he should have been in my room and no reason he should have given me any sort of device.”

Recent conversations between senior U.S. and Russian officials have raised the hope that some substantive dialogue about his case might take place, but the crises and controversies that force those meetings onto White House and Kremlin calendars carry the threat of a major setback.

“The U.S. Embassy [in Moscow] is a lifeline, a literal lifeline, for Paul,” his brother said. “So an invasion and the likely very frosty or outright conflicting diplomatic situation that could occur would make all of that much more difficult.”

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David Whelan can’t speak highly enough of the Embassy Moscow. A series of tit-for-tat diplomatic expulsions, dating back to former President Barack Obama’s punishment of Russia’s 2016 election interference operation, has made it a struggle for U.S. Ambassador John Sullivan’s team even to keep the embassy open, and yet they visit Paul and even play a crucial role in supporting his physical health and well-being.

“Since we don't have a Russian bank account or any way to create a Russian bank account, we don't have any way to get Paul money so that he can get the supplementary foods and vitamins that he needs in order to stay healthy in prison,” David Whelan said.

State Department officials have arranged a multi-step process to deliver money to the imprisoned man. And they even bring provisions directly to the Siberian camp — “the island of the Gulag archipelago which prevailed,” as it has been described — where Paul Whelan is serving a 16-year sentence.

“He is allowed to get four 20-kilogram packages a year, and if they are able to, on one of their trips take one of those packages — which is food, sometimes protein bars and things like that — they do so,” David Whelan said. "They’ve taken nuts before, they’ve taken dried fruit. They are literally helping to make sure that he has the food or basic medicine (like cough drops and things like that) that he needs in order to survive."

He continued, “There’s no way I can say how impressed and grateful I am for the U.S. Embassy staff, those citizen services people. I’m just amazed.”

That assistance could be jeopardized, he fears, if the Russian forces amassed around Ukraine pour over the border in the weeks or months to come. Senior U.S. lawmakers, in an attempt to deter a conflict, have threatened to respond to an invasion by passing legislation disconnecting Russia from the U.S.-led system — an unprecedented punishment that, for all David Whelan knows, would break the financial links that the family and the State Department uses to send money to Paul’s prison account.

“There's a whole chain of people that need to be in place in order for that to happen,” he said. “And if the embassy loses more staff, for example, then that becomes impossible.”

Russian prison wards are not the types to pick up the slack if a crisis generates new diplomatic expulsions. Paul Whelan has been mistreated throughout his time in Russian custody, an ordeal that he has been able to describe to his parents in regular phone calls.

“After the warden threatened me with retaliation for reporting violations of Russian law and human rights abuses, he was arrested for multiple charges of corruption,” Paul Whelan said in a recorded message that was distributed last month by his brother. “A senior prison officer, currently suspended, has been disciplined for his conduct toward me. The warden was punished for trying to cover up the incident. Corruption here knows no bounds.”

The endemic nature of the corruption raises the question, why would the prison wardens face any punishment? David Whelan thinks that Russian authorities have begun to take prison abuse more seriously in the months since a whistleblower leaked videos that showed guards in other sectors of the prison system torturing inmates through acts of sexual violence.

“The government was humiliated,” he said. “There’s a lot of prison abuse and a very intense focus on the prison system right now.”

That reformist pressure to punish prison abuse might be another casualty of any new conflict “as soon as people forget,” as David Whelan put it, with unpredictable consequences for his brother.

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“You know how people get drawn into the daily cycle of what's going on in any certain military conflict,” he said. "I think a lot of the other stories of human rights abuses ... become stories that pretty much nobody in Russia will care about.”