Harvard Law School professor emeritus Alan Dershowitz said Tuesday that the president cannot be charged with obstruction of justice for exercising his authority under the Constitution to pardon or fire someone.

Dershowitz joined CNN's "New Day" to discuss the issue of whether the president can obstruct justice after Trump ‘s attorney John Dowd defended a tweet sent by the president's account and said Trump could not obstruct justice. When Chris Cuomo asked if Dowd's claim was accurate, Dershowitz said in response that the president could obstruct justice "if he engages in acts beyond what Article II of the constitution allows him to do."

"Of course a president can be charged with obstruction to justice if he engages in acts beyond what Article II of the Constitution allows him to do," Dershowitz said. "President Nixon and Clinton were both impeached for obstruction justice by telling witnesses to lie."

The law professor explained why, however, he thinks we shouldn't jump to obstruction of justice charges.

"My point is that the president cannot be charged for simply exercising his authority under the Constitution by pardoning people, by firing people he's allowed to fire, without regard to what his ‘subjective intent' may be," he said.

Dershowitz argued that if a president's behavior is unlawful, it could likely fall under a different charge.

"You can convict the president of bribery; you can convict the president of telling witnesses to lie. What you cannot convict the president of is simply and merely exercising his Article II authority by pardoning somebody or by firing somebody," Dershowitz said. "That's my point. You cannot do that. You may be able to impeach him for misuse of his power, but you cannot prosecute him for exercising his constitutional authority."

Dowd told Axios’ Mike Allen on Monday that the president cannot obstruct justice because he has every right to express his views of any case under Article II of the Constitution.

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," he said.

Dowd was responding to a tweet sent from the president's account over the weekend, a tweet Dowd admits drafting.

"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!" the tweet read.

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! — Donald J. Trump (@realDonaldTrump) December 2, 2017

The president's advisor stands by the tweet, saying it "did not admit obstruction" but he is "out of the tweeting business" and "did not mean to break news."

"The tweet did not admit obstruction. That is an ignorant and arrogant assertion," Dowd said.