In an interview broadcast on the Fox News Channel on Sunday’s “MediaBuzz,” law professor Alan Dershowitz argued that the Mueller team got the law wrong as to whether or not President Donald Trump could be charged with obstructing justice.

Dershowitz explained that a president for carrying out his constitutional duties could not be charged with obstruction and noted that his claim had a past precedent.

“[I]n my introduction, I show how Mueller got the law completely wrong on obstruction of justice,” Dershowitz said. “And I lay out what the law on obstruction is. And you cannot be charged with obstruction if you’re the president and you simply exercise your constitutional authority to fire Comey or anyone else. I lay that out carefully.”

According to Dershowitz, the president was within his authority to fire the director of the FBI and was justified to shut down the investigation under the unified theory of the executive.

Dershowitz cited the precedent of forgiving six former officers accused in the Iran-Contra scandal by George H.W. Bush. The pardons had the intended effect of obstructing the investigation, as determined by Lawrence E. Walsh, the independent prosecutor. Walsh, however, lacked standing to pursue Bush who had exercised his authority to forgive, an issue that continues to be controversial to this day.

“And the best precedent for that is George H.W. Bush, who pardoned Casper Weinberger and five other people on the eve of the trial,” Dershowitz said. “The special prosecutor said he obstructed justice, but he couldn’t be charged with it. And they never mentioned the Bush case in the Mueller report. Mueller was in the Bush administration. Barr was in the Bush administration. And they deliberately omit as the leading precedent, which would preclude a president from being charged with obstruction for simply exercising his constitutional authority.”

Dershowitz compared the “devastating” portrayal of Trump’s actions against James Comey by the special counsel that characterized Hillary Clinton’s use of a private email server as “extremely careless.” Comey announced the decision not to prosecute Clinton, but at the same time described her actions in legally ambiguous terms that helped fuel political opponents ‘ speculation that she had committed a crime, according to WJLA.com.