Donald Trump Jr.’s confirmation that he met with a Russian attorney last year in the hope of obtaining damaging information about the Democratic presidential nominee Hillary Clinton opens a window into Moscow’s motivations for interfering in the 2016 election on his father’s behalf. The main goal of attorney Natalia Veselnitskaya appears to have been to begin talks that might lead to the rollback of a law that, while little known in the United States, has a devastating effect on the personal financial situation of top Kremlin officials and members of Russian President Vladimir Putin’s inner circle.

The New York Times revealed on Saturday that the meeting had taken place in June of 2016. Trump Jr., after initially claiming that the meeting was simply about cross-border adoption rules, acknowledged that in a statement to the Times that he met with Veselnitskaya because he was told she had information that might be damaging to Clinton.

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He said that Veselnitskaya, an attorney with close connections to the Kremlin who was only allowed into the United States on a limited “parole” status after being denied a normal visa, appeared to have little of substance to offer. “It became clear to me that this was the true agenda all along and that the claims of potentially helpful information were a pretext for the meeting,” Trump Jr. told the Times.

What Veselnitskaya really wanted to talk about was the Magnitsky Act, a US law put in place in 2012 to punish Russian officials responsible for the death of Russian attorney Sergei Magnitsky.

Who was Sergei Magnitsky?

Magnitsky was an attorney and auditor with the Moscow-based law firm Firestone Duncan, founded by two Americans in the years when Russia in general and Moscow, in particular, was seen as a land of great economic opportunity.

Magnitsky, as part of the firm’s work for an American investment fund, Hermitage Capital, uncovered a massive multi-billion-dollar tax fraud scheme that implicated senior government and law enforcement officials in the Russian government.

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After it became public that Magnitsky had gathered information about corruption at high levels in the Kremlin, Firestone Duncan’s offices were raided and Magnitsky himself was jailed. He developed multiple illnesses in prison and was not only denied medical treatment but was subjected to brutal beatings. He died in a prison cell in 2009, beaten to death by his guards. Russian courts tried Magnitsky posthumously on tax fraud charges and declared him guilty.

What is the Magnitsky Act?

In 2012, the US Congress unanimously passed, and President Obama signed the Russia and Moldova Jackson-Vanik Repeal and Sergei Magnitsky Rule of Law Accountability Act of 2012. The bill barred specific Russian officials implicated in the Magnitsky case from entering the United States and, more importantly, from using or accessing the US banking system.

Because of the importance of the US financial system to the global banking system, a ban in the US has effects that extend far beyond the country’s borders. Foreign banks that operate in the US and, for instance, take advantage of large US banks’ transaction processing abilities, generally shun account holders who are banned from the US system for fear of running afoul of US regulators.

While nominally affecting only a limited number of Russian officials, the Magnitsky Act was used as a model for future sanctions applied to senior Kremlin officials following the Russian invasion of Ukraine the following year.

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What was happening at the time of Trump Jr.’s meeting?

Veselnitskaya’s appearance in Trump Tower last year came just weeks after a broader version of the law, the Global Magnitsky Human Rights Accountability Act, had been unanimously approved by a key Senate Committee and sent to the full Senate to be considered for a vote. At the same time, a companion bill was making its way through the House of Representatives.

The bill would have given the US president the authority to apply similar sanctions to human rights abusers around the world, including Russian officials involved in that country’s occupation of parts of Ukraine, the fomenting of civil war in other areas of that country, and ongoing human rights abuses in Syria.

What was on the table?

While Trump Jr.’s claim that his meeting with Veselnitskaya focused on cross-border adoption issues may have seemed strange to people unfamiliar with the fallout from the Magnitsky case, it makes perfect sense in context.

In retaliation for the passage of the bill, the Kremlin barred a long list of Americans from entering Russia. The move was broadly mocked, even by many of those named on the list because of the limited practical impact it had. However, at the same time, the Kremlin imposed a ban on the adoption of Russian orphans by US parents. The move, derided as cruel by adoption agencies trying to place at-risk children in safe homes, remains in place.

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The Veselnitskaya meeting appears to have been an attempt to open a discussion with Trump’s team about the reversal of the Magnitsky Act, and considering the circumstances of the Trump campaign at the time, it also suggests just how important that goal is to Moscow.

Back in June 2016, Trump was broadly expected to lose the November election, possibly by an embarrassing margin. The campaign was still trying to make sure Trump would have enough delegates to the Republican National Convention to officially claim the nomination, and Democrat Hillary Clinton, who has explicitly supported the Magnitsky Act, was cruising toward an expected victory.

The fact that a Kremlin emissary was dispatched to meet with representatives of what was then a long-shot presidential campaign suggests that the pain inflicted by the Magnitsky Act on prominent Russian political figures is very real, and something that likely colors relations between Washington and Moscow to this day.