• Though President Donald Trump has shrugged off calls for his impeachment, he has continued to attack the special counsel’s Russia investigation on social media.
  • At the center of Republican attacks is the former White House counsel Don McGahn, who told investigators Trump had ordered him to fire the special counsel Robert Mueller.
  • House Speaker Nancy Pelosi is opposed to impeaching the president, but the Democratic presidential challengers Elizabeth Warren and Kamala Harris support it.
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President Donald Trump on Sunday said he was 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 impeachment behind closed doors and worked out an aggressive strategy to respond.

Citing two sources close to the White House, The Times reported Tuesday that Trump thought the only way to protect himself from impeachment was to attack the special counsel Robert Mueller and the former White House counsel Don McGahn. Thursday’s release of Mueller’s report into Russian election meddling and possible obstruction of justice by Trump revealed the extent to which McGahn cooperated with investigators.

Trump, according to The Times, is not moved by concerns that attacking McGahn could backfire by highlighting McGahn's testimony, which included claims that Trump tried to have Mueller fired.

Details provided by McGahn are central to the arguments of those who have called for the president to be impeached.

The release of the redacted report has reignited debate among Democrats over whether to file articles of impeachment against the president.

One side of the debate argues that Democrats should pursue claims that Trump obstructed 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 activity seems to substantiate the idea that his response to impeachment talk is to lash out.

Trump McGahn

Foto: Don McGahn, then the White House counsel, behind Trump during a Cabinet meeting at the White House on June 21.sourceREUTERS/Jonathan Ernst

"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.