Washington (CNN) Reports surfaced this week that former Donald Trump campaign manager Paul Manafort had decided to register as a foreign agent due to past work he had done on behalf of foreign governments. How big a deal is this? And what did it mean -- if anything -- for the ongoing investigation into Russia's attempts to influence the 2016 election?

In search of answers, I reached out to CNN Justice Department correspondent Evan Perez. Our conversation, conducted via email and lightly edited for flow, is below.

Cillizza: It was big news that former Trump campaign manager Paul Manafort was registering as a "foreign agent." Why?

Perez: Paul Manafort isn't unusual in Washington. It's common for people who represent foreign governments on K Street to avoid registering as foreign agents. That's in part because the law is fairly invasive and allows the government to get into a lot of matters that people would rather the government not get into. Manafort has spent much of his career representing some controversial clients, ranging from the Marcos regime in the Philippines to the pro-Russian government of Viktor Yanukovych, who was accused of rampant corruption during the time he ran Ukraine.

But it's the Ukrainian work from 2012-2014 that has caused so many problems for him, because at the same time he became part of the Trump presidential campaign, the Russians were also trying to meddle in the US election, according to the US intelligence agencies. That's why it's a big deal to finally decide to register as a foreign agent. Particularly because he was acting on behalf of a pro-Russian regime in Ukraine.

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