Harvard law professor Alan Dershowitz explained why motives are bad indicators of obstruction of justice during a Sunday interview on NBC’s “Meet the Press.”

WATCH:

NBC anchor Chuck Todd pointed to recent comments by Rudy Giuliani that claimed the president fired James Comey because he wouldn’t state publicly that Trump wasn’t under investigation. Todd wondered if Giuliani’s comments gave Mueller a stronger case for obstruction of justice.

“Motives are complex,” Dershowitz explained. “That’s why motives should never form the basis of a crime. That’s why it’s wrong to question what a president’s motives are when the president acted within his constitutional authority.”

“We don’t want to turn motives and analysis of the president’s mind into criminal statutes. We have to look at what the president did not what his motives are because motives are always complex,” he continued. “We see complex motives at work.”

Dershowitz also added that he wishes the Trump legal team would use his defense to argue against obstruction.

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