CNN's David Gergen told host Don Lemon that the news Jeff Sessions did meet with the Russian ambassador twice, but didn't disclose those meeting while under oath is, "a deeply disturbing and embarrassing story for the Attorney General."

Earlier in the program Jeffrey Toobin said Sessions could face up to five years in prison for lying under oath at a Senate confirmation hearing.

Gergen agreed that at a minimum Sessions should recuse himself from investigating the Russia ties story.

He was a little suspicious at the timing of the report, but added, "When you testify at confirmation hearing, you spend a lot of time preparing that with other lawyers and others who really grill you -- and you have to think through answers in advance."

Gergen continued, "These are not casual conversations when you testify in confirmation hearings, or indeed anytime you testify under oath before the Congress.

"So, he had to have looked at his calendar. His team had to have looked through his calendar, gone through this with him and to plead 'I can't remember,' that -- does that seem credible given the kind of preparation he would have to go through?"

Trump's surrogates were out in force this morning, but this is not easily deflected. Sessions knew he met with the Russians and could have brought it up at anytime during his hearing or to the written answers to the questions he received.

He chose not to disclose those meetings.

As Gergen stated, Sessions' statements wouldn't be credible if he says he "misunderstood" or "forgot." That's not an option for the AG to have, especially after all the preparation that is involved in the confirmation process.