Watergate reporter Carl Bernstein ridiculed the "lying of the president" regardless of whether he might be "criminally covering up events" or not.

"There's no reason to believe almost anything Donald Trump says," Bernstein, a frequent critic of President Donald Trump, told CNN's "State of the Union" on Sunday.

"Because what we know is that the president of the United States and his presidency is characterized, above all else, by the lying of the president of the United States."

Amid talk of potentially firing FBI special counsel Robert Mueller and/or pardoning those indicted in the investigation of Russia's influencing the 2016 presidential election, Bernstein says "lying" is not a crime, unless of course, it results in a provable criminal cover-up.

"That doesn't mean that lying by the president is a crime," Bernstein continued. "It does mean that we see him covering up events, but not necessarily criminally covering up events.

"And where this is going, definitively, we don't know."

Bernstein said President Trump's lawyers are telling him "what he wants to hear," and they have "an out-of-control client."

"The president of the United States, in their view, is out of the control a good deal of the time, especially when it comes to this investigation," Bernstein told CNN.