A former Watergate prosecutor late Wednesday criticized President Trump's attorney Rudy Giuliani over his explanation that Trump was merely issuing an "opinion" when he called for Attorney General Jeff Sessions to end the special counsel probe.

"I think it’s a very weak defense," assistant Watergate special prosecutor Jill Wine-Banks said on MSNBC's "The Last Word with Lawrence O'Donnell."

"It is a question for the jury as to whether 'should' is an order or just an opinion. And I think when presented to a jury, they would find in the context of all of the other tweets that the president has done and all the other actions he has taken, including the firing of [former FBI Director] James Comey, that they would find the word 'should' was an order."

Wine-Banks argued that Trump's tweet on Wednesday calling for Sessions to immediately end the probe into Russian interference in the 2016 presidential election was sent with the intention that Sessions obey it and that Trump has "undermined" the probe from the beginning.

Sessions, who previously served as an adviser to the Trump campaign, recused himself from probes involving Russia last year. Sessions's recusal left his deputy, Rod Rosenstein, as the highest-ranking Justice Department official overseeing the probe. Rosenstein then appointed Robert Mueller as special counsel after Trump fired Comey.

"He has polluted any possible impact on a potential jury in any case because of what he is saying," Wine-Banks argued of Trump on MSNBC.