John Dean: Sessions firing seems 'planned like a murder'

"I think this seems to be planned like a murder," Dean told CNN's Jake Tapper on "CNN Newsroom." "I say that given the fact the President was asked the question in the press conference this morning -- he brushed it off, said 'we'll deal with it later.'"

"'Later' meant he's not going to necessarily fire Mueller, he's going to undercut him by the people around him," Dean continued.

Dean, a frequent critic of Trump, is known for his cooperation with prosecutors during the Watergate investigation. He added Wednesday that he felt it's "almost impossible" to not see Sessions' firing as an attempt to undermine special counsel Robert Mueller and his investigation into Russian interference in the 2016 election.

"It is almost impossible not to interpret this in any other way than the fact to undercut Mueller," he said. "But I also think Mueller has been well aware of that and probably has planned for that contingency."

Trump officially fired Sessions on Wednesday after repeatedly attacking the former Alabama senator in rallies and tweets.

"We thank Attorney General Jeff Sessions for his service and wish him well!" Trump tweeted. When asked about changes to his administration in a press conference earlier Wednesday, Trump did not mention Sessions.

Dean said Wednesday that despite the potential implications Sessions' firing could have on the Mueller investigation, he still has faith in the justice system, including the conservative-leaning Supreme Court.

"The system is not just five judges that are conservative on the Supreme Court. It is an entire branch of the government and even for those five justices, if they do lean toward the President, to do precedent breaking action makes us look like a banana republic -- you could start losing one or more of those five," he said.

"I have an underlying faith in the system."