David Gergen, who served as an adviser to four presidents over the years, said on Friday that the damage-control effort following the revelation of Donald Trump Jr. agreeing to meeting last year with a Kremlin-linked lawyer promising dirt on Hillary Clinton "may go down as one of the most incompetent cover-ups we have ever had."

Gergen made the comment during an evening panel on CNN, where he is a senior political analyst, talking about the "stupidity" of efforts by Trump Jr. and his father, President Trump, which have resulted in a number of ever-changing explanations of the June 2016 meeting as more details about it have been reported by the media.

He described the White House as being pulled into a "vortex" of sorts, though he conceded that "we don't know, of course, whether this meeting brought violations of the law."

"But we do know in the aftermath there has been a pattern, a very clear pattern of dishonest, misleading statements that — and that represents stupidity as well. Because clearly more was going to come out," Gergen said. "And for them to issue a statement that made it all look very innocent about adoption of children. And we've had now three versions and disturbingly, the New York Times, CNN points has pointed out, that Donald Trump himself apparently approved at least two of the misleading statements and they've been blown out of the water."

He added, "This may go down as one of the most incompetent cover-ups we have ever had." When asked if he meant that statement by host Anderson Cooper, Gergen replied, "Absolutely."

.@David_Gergen: Russian meeting "may go down in history as one of the most incompetent coverups we've ever had" https://t.co/vXWx3MzdQt— Anderson Cooper 360 (@AC360) July 15, 2017

Trump Jr.'s version of events has been amended repeatedly over the course of the week. Initially, in response to the New York Times' first report last weekend, Trump Jr. said the meeting focused on Moscow's ban on the adoption program of Russian children by U.S. citizens, and didn't mention anything related to the 2016 campaign. That response was reportedly approved by President Trump himself. After the Times reported the next day that Veselnitskaya promised damaging information on Clinton, Trump's Democratic campaign rival, he said in a new statement that Veselnitskaya provided "no meaningful information."

Gergen said he doesn't think it's possible to believe what Trump Jr. and his team are saying about the outcome of the meeting, considering the continued outpouring of new information about it.

More revelations about that meeting have been reported throughout the week, and on Friday it was revealed that at least eight people were present at the meeting, adding to the original lineup of Trump Jr., former Trump campaign manager Paul Manafort, Trump's son-in-law and current adviser Jared Kusher, and Russian attorney Natalia Veselnitskaya. All together, six have been identified, including an ex-Russian spy who denies any current connection to Russian intelligence.

Critics have said this meeting is evidence of collusion between the Trump campaign and Russia, which members of the U.S. intelligence community say meddled in the 2016 election to help Trump's chances.

Fellow CNN commentator, former Obama adviser David Axelrod, on Thursday rebuffed Trump Jr. and the Trump administration for defending the meeting as attempt to obtain "opposition research," and said it "is very close to espionage."