Special counsel Robert Mueller, who is investigating Russian meddling in the 2016 U.S. presidential election, has job security after he brought felony charges against President Donald Trump's onetime campaign chairman, a former assistant U.S. attorney told CNBC on Monday.

"Trump would be impeached the next day if he tried to remove Mueller," said John Lauro, who was a federal prosecutor in the Eastern District of New York from 1986 to 1988 during the presidency of Ronald Reagan.

"He can't be fired by the president of the United States. There's no way," Lauro told "Squawk on the Street."

Paul Manafort, the onetime chairman of the Trump campaign, surrendered to authorities on Monday after he was indicted on 12 counts related to money laundering, including "conspiracy against the United States." A former Manafort colleague, Rick Gates, also has been charged.

"The significance of the indictment is it gives Mueller cover now going forward," Lauro said. "Nobody is going to touch him because Paul Manafort is under indictment. And second, it gives him an opportunity to press Manafort for information."

Lauro says U.S. authorities will use the indictment to put pressure on Manafort to "flip" or "cooperate" in the investigation. The government doesn't indict until it has all the information locked down, he added.

Trump has dismissed any suggestion that his campaign colluded with Russia in the 2016 election. On Monday, Trump responded to the news, and said the alleged crimes by Manafort occurred years before he joined the 2016 campaign.

Lauro said people should expect more indictments.



A spokesman for Manafort did not respond to a request for comment from CNBC on Monday. A spokesman for Gates could not immediately be located.



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