WASHINGTON — The first charges were filed Monday as part of special counsel Robert Mueller's investigation into any links between the Russian government and Donald Trump's presidential campaign.

A federal grand jury charged Trump's former campaign chairman Paul Manafort and campaign associate Rick Gates with multiple counts, including money laundering and conspiracy, related to their work for a foreign government.

Both men pleaded not guilty during court appearances Monday in federal court in Washington, D.C.

In addition, George Papadopoulos, a former foreign policy adviser to Trump’s presidential campaign, pleaded guilty earlier this month to making false statements and “material omissions” to the FBI about the nature of links between the Trump campaign and the Russian government, according to documents released Monday.

The developments, while significant, are still a long way from resolving the question of whether there was collusion between any Trump associates and Russia to influence the 2016 election.

Here's what we know so far.

What did Manafort and Gates allegedly do?

The indictment alleges the pair worked for the government of Ukraine from at least 2006 to 2015 but did not register as lobbyists for foreign government as required by law. To hide the tens of millions of dollars they were paid, Manafort and Gates laundered money through scores of U.S. and foreign corporations, partnerships and bank accounts, according to the indictment. Manafort allegedly used his hidden wealth to enjoy a "lavish lifestyle" without paying taxes on the income. Gates used money from offshore accounts to pay for such personal expenses as his mortgage, children's tuition and interior decorating of his Virginia residence, according to the indictment.

What are the charges?

Manafort has been charged with nine counts — including conspiracy, money laundering, failing to register as a foreign agent, failing to disclose foreign banking activity and making false statements. Gates was charged with eight of the same counts.

Why were they charged with conspiracy against the U.S.?

The first count against Manafort and Gates charges them with conspiracy against the United States. Despite what it might sound like, however, the charge is not related to any allegation of collusion with the Russians to affect the 2016 election. Instead, the charge accuses Manafort and Gates of agreeing to do something illegal, in this case not reporting foreign banking activity, their lobbying work for a foreign government, and not truthfully answering questions about their activities. In legal terms, that means they "conspired to defraud" the country by obstructing the Justice and Treasury departments' functions.

What are the penalties for the charges?

The two men each could face up to 40 years in prison and potentially millions of dollars in fines. The money laundering counts alone carry a maximum 20-year sentence and a fine of up to $500,000 or twice the amount of the funds involved.

What work did Manafort and Gates do for their clients?

In 2006, a pro-Russia political party in Ukraine, the Party of Regions, allegedly hired Manafort's lobbying and public relations firm in part to help its candidates win elections. The party's presidential candidate, Victor Yanukovych, was elected president in 2010. He fled to Russia in 2014 after a popular uprising.

According to the indictment, Manafort and Gates tried to disguise their work in part by using the European Center for a Modern Ukraine to advocate on behalf of the Ukranian government. The center, created around 2012, nominally hired two Washington, D.C.-based firms to lobby Congress on sanctions against Ukraine, the validity of the Ukranian elections and other matters. But Manafort and Gates had arranged the hiring, directed the work, and the center was actually under the control of Yanukovych and the Party of Regions, the indictment alleges.

The center ceased to operate after Yanukovych fled Ukraine.

Who is Paul Manafort?

Manafort, 68, is a longtime lobbyist and political operative who has worked for Republican campaigns dating back to Gerald Ford and Ronald Reagan. In 1980 he founded the consulting firm of Black, Manafort, Stone & Kelly.

Manafort was a key player in the early stages of the Trump presidential campaign. When campaign manager Corey Lewandowski was fired in June, Manafort took the reins, helping the Trump campaign wrangle delegates for the Republican National Convention. Gates signed on as Manafort's deputy. But Manafort was forced out by Trump in August amid questions about the campaign's tactics and his Russian ties.

Who is Rick Gates?

Gates, who is described in the indictment as Manafort's "right-hand man," had worked with Manafort in the private sector and followed him to Trump's campaign in 2016. Gates wound up moving to the Republican National Committee when Manafort was ousted from the campaign, and he helped set up a pro-Trump super PAC after the election.

Who is George Papadopoulos?

Papadopoulos served as a foreign policy adviser to the Trump campaign. He lied to federal investigators about his interactions with a professor with ties to the Kremlin, according to the statement of offense filed Monday. The professor told Papadopoulos that the Russians had "dirt" on then-candidate Hillary Clinton in the form of "thousands of emails."

Papadopoulos claimed that his interactions with the professor occurred before he joined the campaign.

But "in truth and in fact," the criminal statement says, Papadopoulos learned he would be an adviser to the campaign in early March, and he met the professor on or about March 14, 2016. The professor "only took interest" in Papadopoulos because of his role in the campaign, and the professor told Papadopoulos about the "thousands of emails" on or about April 26, 2016, when he had been on board with the Trump operation for more than a month.

Papadopolous pleaded guilty to the charge earlier this month, but it was kept secret until Monday, when charges were also unsealed against Manafort and Gates.

What do these developments mean?

The indictments are the first shoe to drop in the wide-ranging Mueller probe, which is only one part of the multi-faceted investigation into Russian involvement in the 2016 election.They're a sign that the probe will continue despite Trump's attempts to end the investigation as a meritless fishing expedition.

The indictments also show that Mueller is willing to dig back before the election into questionable activities by Trump aides as possible precursors to the activities that affected the campaign.

Papadopolous' guilty plea shows the first evidence that members of Trump's campaign directly coordinated with Russian officials to collect damaging information on opponents. Collecting such information is routine in presidential campaigns, but the involvement of a foreign government is highly problematic.

How did President Trump react to the indictments?

Trump tweeted that the illegal acts Manafort has been charged with happened before Manafort joined Trump’s campaign. He also said the investigation should be focusing on “Crooked Hillary” and the Democrats.

“Also, there is NO COLLUSION!" he added.

How did Democrats react to the indictments?

Senate Minority Leader Chuck Schumer, D-N.Y., warned Trump against interfering with Mueller’s investigation. “If he does so, Congress must respond swiftly, unequivocally, and in a bipartisan way to ensure that the investigation continues," Schumer said in a statement.

House Minority Leader Nancy Pelosi, D-Calif., said an “outside, fully independent investigation” is still needed even with Mueller’s “accelerating” investigation and the work of congressional committees.

Contributing: Kevin Johnson, Brad Heath, John Bacon, Kevin McCoy and Deirdre Shesgreen

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