Rep. Justin Amash is not backing down for his calls for President Donald Trump's impeachment.

In a series of tweets on Monday, the Michigan Republican disputed several talking points that Republicans, including Trump, have suggested as reasons the president did not commit obstruction.

Amash, a founder of the conservative House Freedom Caucus, has become the lone Republican calling for Trump's impeachment.

He argued in his tweets that there were underlying crimes detailed in special counsel Robert Mueller's probe into whether Russia colluded with Trump's 2016 campaign, which also widened to investigate possible obstruction of justice.

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The congressman went on to note that underlying crimes are not necessary to be charged with obstruction.

"In fact, obstruction of justice does not require the prosecution of an underlying crime, and there is a logical reason for that. Prosecutors might not charge a crime precisely *because* obstruction of justice denied them timely access to evidence that could lead to a prosecution," he wrote in a tweet, which many legal experts have also said.

Amash's counterpoint Twitter thread comes a day after Trump called out the Michigan Republican.

The president tweeted Sunday that he was "never a fan" of Amash, adding that he is a "a total lightweight who opposes me and some of our great Republican ideas and policies just for the sake of getting his name out there through controversy."

"Justin is a loser who sadly plays right into our opponents hands!" Trump wrote, adding that he doesn't think that Amash actually read Mueller's report.

Mueller detailed 10 potentially obstructive acts in his investigation, and noted that "while this report does not conclude that the President committed a crime, it also does not exonerate him." Attorney General Bill Barr and then-deputy Attorney General Rod Rosenstein, however, did not charge the president with obstruction.

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Barr argued that because Mueller's report concluded that members of Trump's campaign did not conspire or coordinate with Russian officials to interfere in the 2016 election, then the president could not have obstructed justice because there was no crime to cover up in the first place.

Mueller's report did note that the Russian government interfered in the election to work to secure Trump's victory.

Many Democrats, including those who are running for president, have called for Trump to be impeached. However, House Speaker Nancy Pelosi has called impeachment the "most divisive" path and has not moved forward with any plans.

Several top Republicans have come out against Amash's stance.

House Minority Leader Kevin McCarthy, R-Calif, claimed the Michigan Republican wants attention

“It’s a question whether he’s even in our Republican conference as a whole,” McCarthy said during an interview on Fox News. “What he wants is attention in this process. He’s not a criminal attorney. He’s never met Mueller. He’s never met Barr. Now he’s coming forward with this because this is what he wants.”

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