Trump reportedly thinks the Mueller report is an existential threat, and that the only way out is a relentless attack on everyone involved

AP Photo/Pablo Martinez Monsivais

President Donald Trump inside his armored SUV in Mar-a-Lago, Florida, ahead of an Easter church service on April 21, 2019.

• Despite President Trump shrugging off calls for his impeachment, he has continued to attack the Mueller probe on social media.
• At the center of Republican attacks is former White House counsel Don McGahn, who said he resisted Trump's orders to fire Mueller.
• House Speaker Nancy Pelosi is currently opposed to impeaching the president, but Democratic presidential challengers Elizabeth Warren and Kamala Harris support it.
• Visit Business Insider's homepage for more stories.

President Donald Trump on Sunday said he is not "a little bit" worried by calls for his impeachment that rumbled over the weekend.

But reports and the president's social media attacks indicate that the issue is very much on his mind.

According to the New York Times, Trump has expressed concerns about potential impeachment behind closed doors, and worked out an aggressive strategy to respond.

Citing two sources close to the White House, The New York Times reported Tuesday that Trump believes that the only way to protect himself from impeachment is to attack the sources of the damning accounts: former White House counsel Don McGhan and special counsel Robert Mueller.

He is reportedly not moved by concerns that attacking McGahn will backfire, by highlighting McGhan's claims that Trump tried to have Mueller fired.

The claims are central to the arguments of those who have called for the president to be impeached.

Following the release last week of the redacted report by special counsel Robert Mueller into Russian collusion, debate has raged among Democrats over whether to file articles of impeachment against the president.

One side of the debate argues that Democrats should pursue claims of obstruction of justice. The other says Democrats should refocus, citing concerns that dragging on the fight could turn off voters.

Democratic presidential challengers Senator Elizabeth Warren of Massachusetts and Senator Kamala Harris of California are among those who have openly championed calls for the president's impeachment, but in a phone call with House Democrats Sunday, House speaker Nancy Pelosi expressed opposition to the move.

Trump's recent social media activist seems to substantiate the idea that his response to impeachment talk is to lash out.

REUTERS/Jonathan Ernst

White House Counsel Don McGahn sits behind U.S. President Donald Trump as the president holds a cabinet meeting at the White House in Washington, U.S. June 21, 2018.

"Only high crimes and misdemeanors can lead to impeachment," tweeted the president on Monday, amid a flurry of retweets of allies and Fox News presenters attacking the Mueller probe.

"There were no crimes by me (No Collusion, No Obstruction), so you can't impeach. It was the Democrats that committed the crimes, not your Republican President! Tables are finally turning on the Witch Hunt!"

The tweet marks a shift from his earlier claims of "total exoneration," which he made after a summary of the report was submitted to Congress by Attorney General William Barr in March.

Senator Lindsey Graham of South Carolina-a key congressional ally of the president - in an interview with Fox News' Sean Hannity on Monday predicted that Democrats would seek to impeach Trump.

He said the move would strengthen the president' and boost his changes of re-election in 2020.

"They're going to be stampeded to impeach Trump because they hate him so much, and I hate [that it's happening] for the country, I hate [that it's happening] for the president - but it's going to result in him getting re-elected," said Graham.

Senate Republicans - whose support Democrats would need to impeach the Trump - have stuck by the president following the release of the report, and hailed it as great news for his 2020 campaign.