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President Donald Trump's personal lawyer, John Dowd, revealed Monday a potential legal defense in the ongoing Russia probe, claiming that a president cannot obstruct justice.

"The president cannot obstruct justice because he is the chief law enforcement officer under (the Constitution's Article II) and has every right to express his view of any case," Dowd told NBC News Monday.

Dowd added that the president's weekend tweet — which many have argued strengthened a potential obstruction of justice case for special counsel Robert Mueller — "did not admit obstruction."

"That is an ignorant and arrogant assertion," Dowd said.

His comments were first reported by Axios and came two days after Trump tweeted, "I had to fire General Flynn because he lied to the Vice President and the FBI."

"He has pled guilty to those lies. It is a shame because his actions during the transition were lawful. There was nothing to hide!" Trump wrote in his Saturday tweet — his first public comments about his former national security adviser after Michael Flynn pleaded guilty to lying to the FBI about speaking with Russian officials.

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The tweet caused an uproar in Washington because it suggested Trump knew Flynn had committed a felony — lying to the FBI. Then-FBI director James Comey said earlier this year that the president told him to go easy on Flynn the day after the firing. Trump has denied telling Comey that.

Interfering in the FBI's investigation could be construed as obstructing justice, potentially creating legal jeopardy for Trump, some experts argued.

Attorney John Dowd, President Donald Trump's personal lawyer. Brendan McDermid / Reuters file

But within a few hours of the Saturday post, Dowd stepped in to say that he wrote the tweet, not the president.

Meanwhile, several lawmakers and legal experts immediately weighed in Monday morning to express their disagreement with Dowd's position that the president cannot obstruct justice.

"I hope my Republican colleagues in the U.S. Senate will take the lead on this issue and also on obstruction of justice. There is a credible case of obstruction of justice against Donald Trump," Sen. Richard Blumenthal, D-Conn., said on MSNBC’s "Morning Joe."

"If you take the president's own statement, his tweet that he knew Michael Flynn was lying to the FBI when he fired him, which means that he knew Michael Flynn committed a felony when he asked Comey to stop the investigation of him, and when he fired Comey when he refused to do so, and when he fired Sally Yates and when he called Michael Flynn in April to tell him to stay strong, all of these acts are to impede and obstruct justice," he explained.

Former U.S. Attorney Preet Bharara, who was fired by Trump, acknowledged in an interview with NPR that charging a president with obstruction "is a very high bar, it's a very high threshold, it's a difficult thing, it's never been done before."

"But the mere fact that the president is the president doesn’t immunize him from an accusation of obstruction," Bharara said.

The articles of impeachment against both former Presidents Richard Nixon and Bill Clinton included charges of obstruction of justice.

But another prominent legal expert defended Dowd's theory.

"You cannot charge a president with obstruction of justice for exercising his constitutional right to fire Comey and his constitutional authority to tell the Justice Department who to investigate, who not to investigate," Harvard Law Professor Emeritus Alan Dershowitz told Fox News Channel on Monday. "For obstruction of justice by the president, you need clearly illegal acts."

“The president could've pardoned Flynn if he were really thinking about trying to end this investigation. He would've pardoned Flynn and then Flynn wouldn't be cooperating with the other side and the president would've had the complete authority to do so," he added. "So I think the fact that the president hasn't pardoned Flynn even though he has the power to do so is very good evidence that there's no obstruction of justice going on here."