By Maegan Vazquez, CNN

(CNN) -- President Donald Trump's personal attorney, John Dowd, claims the President cannot be guilty of obstructing justice, according to an interview with Axios.

"(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 Axios.

The new defense comes after a tweet from Trump's account suggested the President knew former White House national security adviser Michael Flynn had lied to the FBI when he was fired in February, raising questions about whether Trump knew about Flynn's lying before pressuring former FBI Director James Comey to let go of inquiries into Russian election meddling.

The position that Trump cannot obstruct justice -- which evokes a similar claim once made by former President Richard Nixon, who resigned over the Watergate scandal -- is sure to be debated as special counsel Robert Mueller's investigation intensifies. Flynn is the first administration official to be charged as part of the probe.

The @realDonaldTrump account tweet was pushed out after Flynn pleaded guilty to lying to the FBI about his conversations with the Russian ambassador to the US during the presidential transition.

"I had to fire General Flynn because he lied to the Vice President and the FBI," the Saturday tweet reads. "He has pled guilty to those lies. It is a shame because his actions during the transition were lawful. There was nothing to hide!"

Dowd has said he drafted the tweet, but denied that it admitted obstruction.

"That is an ignorant and arrogant assertion," Dowd told Axios.

Former Obama administration White House counsel Bob Bauer disputed Dowd's position.

"There is no express grant of immunity under the Constitution to protect the President who commits a felony," he told CNN. "Those who have argued for it have to cobble together their case primarily out of a concern about the debilitating effects of a President in legal trouble on the conduct of government. But they have a high burden to carry in claiming that the President charged with faithful execution of the law is above it. It simply contravenes basic understandings about the rule of law in the constitutional order -- as Richard Nixon learned in trying to withhold his incriminating tapes."

Former Trump campaign adviser Michael Caputo told CNN's "New Day" Monday morning that he doesn't believe Trump knew that Flynn lied when he spoke to Comey but added that Trump's tweet complicates the investigation.

"Well, I think (in) obstruction of justice, you have to prove both falsification and concealment," Caputo said, later adding that "if we're going to be, you know, taking apart these tweets that are coming out, obviously tweets about ongoing cases are pretty inadvisable."

Caputo also asserted that since there haven't been charges of collusion yet, there was no collusion at all.

"We know now, especially with the Flynn charges, that there is no Russian collusion being alleged anymore. It's all about obstruction. He's the fourth Trump campaign official, the second high-ranking one, who's been out there and accused of crimes. And there's not one word of Russian collusion," he said.

But the fact that a former national security adviser -- one of the most senior members of the government -- is not Mueller's primary target, as evidenced by the plea deal, suggests Flynn is being used as bait for a bigger target. And it may be a sign Mueller does not intend to end his investigation merely by indicting people on the charges lying under oath, as some previous independent prosecutors of government wrongdoing have done.