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Jacquelyn Martin, AP
People enter the Federal Court, Monday, Oct. 30, 2017, in Washington. President Donald Trump's former campaign chairman, Paul Manafort, and a former business associate, Rick Gates, have been told to surrender to federal authorities Monday, according to reports and a person familiar with the matter. (AP Photo/Jacquelyn Martin)

Paul Manafort, President Donald Trump’s former campaign chairman, and Rick Gates, a former business associate of Manafort, were indicted Monday by special counsel Robert Mueller, moving the probe into Russia's involvement in the 2016 election into a new phase.

Moments after the indictment was released, news broke that former Trump campaign adviser George Papadopoulous pleaded guilty three weeks ago to lying to FBI agents about his contact with Russia.

Here’s a quick breakdown of what you need to know.

Why this matters: Papadopoulous' plea is "the first criminal count that cites interactions between Trump campaign associates and Russian intermediaries during the campaign," the Associated Press reported. Coupled with the separate Manafort and Gates indictment on conspiracy against the United States, the developments usher "Mueller’s sprawling investigation into a new phase with felony charges and possible prison sentences for key members of the Trump team," AP added.

What charges do Gates and Manafort face?: According to the AP, they face “felony charges of conspiracy against the United States, acting as an unregistered foreign agent, and several other financial counts involving tens of millions of dollars routed through offshore accounts.”

Head to ABC News to read the entire indictment.

What is the status of Manafort and Gates?: Both pleaded "not guilty" following the indictment, according to NBC.

What did Papadopoulous do?: The court documents said that Papadopoulous attempted to arrange a meeting between Russia and the Trump campaign.

Papadopoulous learned that Russians had “dirt” on Trump’s presidential opponent, Hillary Clinton, and spent months trying to set up a meeting between Trump and Russian officials, which didn’t happen, according to the prosecutors, BuzzFeed News reported.

The court released documents on the criminal charges against Papadopoulos. You can read the full text at CNN.

Papadopolous response: Papadopoulos' attorney's released a statement:

What does this mean for Trump?: According to FiveThirtyEight, Papadopoulous appears to be working with Mueller's investigation and that "could still be bad for Trump" because Papadaopolous' activities tie Trump's campaign officials with Russia.

One email contained in court documents has Papadopoulous saying it was important that "DT" isn't conducting the trips with Russia, and that "someone low level" does instead.

Though it's unclear who that "low level" person is, "the fact that the other two people on the email thread were also indicted Monday — and that Papadopoulos is now in a position to explain the context of all of the exchanges cited in the charge to Mueller’s team — isn’t good news for Trump or the people in his orbit," according to FiveThirtyEight.

The charges against Manafort and Gates don’t "reference the Trump campaign or make any allegations about coordination between the Kremlin and the president's aides to influence the outcome of the election in Trump's favor," according to AP.

White House response: Press Secretary Sarah Huckabee Sanders said the indictments have nothing to do with the White House.

"Today's announcement has nothing to do with the president, and has nothing to do with the president's campaign, or his campaign activity," she said, according to CNBC.

Sanders also said that Papadopolous was a volunteer for the campaign.

Trump’s response: Trump responded to the news on Twitter.

Trump's past comments: In March 2016, Trump called Papadopoulous an “excellent guy,” according to The Washington Post.

How Americans view it: An Axios-SurveyMonkey poll taken last week found that 54 percent of Americans feel Russia's use of technology to influence U.S. politics is a serious issue that should be investigated. Meanwhile, 41 percent said it was a distraction.

A Public Religion Research Institute poll in August found that fewer than half (48 percent) of Americans believe there is clear evidence that Russia interfered in the 2016 presidential election to help the Trump campaign. The report showed that 80 percent of Democrats felt that way, while 20 percent of Republicans feel the same.