They hope to persuade other countries to follow Washington's example in creating a "Magnitsky list," which refuses entry to 16 officials implicated in the attorney's prosecution and death and freezes their assets. Activists in Britain and elsewhere are urging their governments to adopt a larger list of 60 names published by the U.S. Helsinki Commission.
How much Russia wants to push back against these initiatives was on ample display on July 11 as a Russian court sought to discredit the efforts by finding Sergei Magnitsky guilty, posthumously, of tax evasion.
Similarly, the court sought to discredit the main international campaigner for Magnitsky sanctions, William Browder, by convicting him, too, of tax evasion and sentencing him in absentia to nine years in prison.
But if Moscow is again underlining its readiness to fight the list, those seeking to get more countries to adopt it say they are undeterred.
What progress the Magnitsky list proponents are making -- and how high the stakes are -- were equally on display this week ahead of the Russian court decision.
The center of attention was Britain as London and Moscow apparently engaged in a complicated ballet over whether London is ready to blacklist Russian officials implicated in the case even without formally adopting a Magnitsky list.
U.K. 'Magnitsky List' Mentioned
The drama started with a report by "The Daily Telegraph" that the country's immigration authority had taken measures to assure listed individuals could not enter the United Kingdom.
The newspaper noted that a statement by Immigration Minister Mark Harper had been published on July 8 in the British Parliament's permanent record.
"The Home Office special cases directorate is already aware of the individuals and has taken the necessary measures to prevent them being issued visas for travel to the U.K.," Harper stated.
The statement was in reply to a question submitted in April by British Member of Parliament (MP) Dominic Raab asking the minister if any of the 60 people named in the U.S. Helsinki Commission list had visited Britain during the past year. Raab is a vocal campaigner for Britain to adopt its own Magnitsky sanctions.
...And Then Un-Mentioned
Within hours, the news was picked up by the Russian press and caused a furor in Moscow.
A clearly surprised Foreign Minister Sergei Lavrov questioned whether it was an accurate statement of London's position. "We have not received any official notification from British authorities on this matter," he said. "Furthermore, Britain's authorities have previously stressed, more than once, that they were not going to introduce any such lists."
WATCH: The verdict on Sergei Magnitsky and William Browder is read aloud in court.
What followed next was an apparent backtracking by the British government. On July 9, Harper requested that his original answer to Raab be struck from the parliamentary record and replaced with a more cautious one.
In his new response, Harper wrote: "We are aware that some individuals have been linked to the arrest, detention, and death of Sergei Magnitsky. Any application for a visa to come to the U.K. will be considered on the individual merits of the case in line with our usual practice."
"The Daily Telegraph" reported that the government had realized that its "unguarded statement could prove hugely sensitive at a time when the U.K. is trying to build a trade bridge with Russia to help British exporters."
Proponents See Progress
But if some observers saw the events as a measure of London's reluctance to talk about sanctions openly, proponents of a U.K. Magnitsky list viewed the flap positively.
"Regardless of the histrionics from the Putin regime, I think the government here has made it pretty clear that those 60 are subject to flags that would go up if they ever try to enter the country," Raab told RFE/RL. "And I think it would be, actually, politically very contentious if subsequent to the answer, even as clarified, it were to be found out that they had entered the country. I think that alone makes it very unlikely that they ever would."
Raab called that a step forward in the longer fight to get Britain to adopt legislation that could enact visa bans and asset freezes against Russian officials connected to the Magnitsky case.
"This is part of a step-by-step process towards a U.K. Magnitsky act. I think we'll get one," Raab said. "I'm not quite sure what form and I'm not sure whether it will be sooner rather than later, but actually, this is two steps forward and one step back rather than the reverse."
Browder, the CEO of U.K.-based investment firm Hermitage Capital Management, who was Magnitsky's client when the lawyer uncovered fraud, told RFE/RL he doubted that the British government's revision makes any difference in practice. "I don't think that they did visa bans and then they undid visa bans," he said.
Moscow Shows Its Teeth
"What seems to be going on is the same thing that has been going on in just about every country in the world, including the United States, which is that the situation surrounding the Magnitsky case is so horrible that most governments can't with a straight face not do something about it," Browder added.
"But at the same time, the Russians are so evil in their approach towards anybody wanting to do something about it that governments are scared."
When the United States slapped visa bans and asset freezes on 18 individuals in April, the move was a hard-won victory for lawmakers, who overruled the Obama administration's opposition. Moscow responded with its own blacklist of U.S. officials and a ban on adoptions of Russian children by U.S. citizens.
Sanctions supporters have since turned their focus to Europe, where Russian officials more frequently travel and keep more of their assets.
They have faced a struggle there as well. Repeated calls by the European Parliament to enact EU-wide Magnitsky sanctions have gone unheeded. In May, Ireland dropped plans to impose Magnitsky sanctions after Moscow threatened a ban on Irish adoptions of Russian children.
The 37-year-old Magnitsky died under allegedly torturous jail conditions in 2009 after implicating Russian officials in a scheme to steal $230 million from state coffers. He was then prosecuted by some of the same officials he had implicated.
Moscow has failed to convict any of the dozens of individuals that supporters, Western lawmakers, and NGOs say were behind Magnitsky's prosecution and death. His case has come to represent Russia's troubling record on the rule of law and human rights.