A string of high-profile gaffes within the past 24-hours have renewed doubts, especially on the left, over former Vice President Joe Biden’s capabilities as a candidate. When Biden first appeared in Iowa this week, it was as a returning champion. Not only had the frontrunner bested his most vocal challenger at the second Democrat presidential debate last week, but Biden had also succeeded in deflecting some of the attention from his mounting family troubles by attacking President Donald Trump.

Even critics, like former Obama strategist David Axelrod, admitted Biden’s campaign seemed to be finding its groove.

“By far, this is best Joe Biden moment of the campaign,” Axelrod tweeted after Biden delivered a speech accusing Trump of having fanned ‘the flames of white supremacy.’ “He is speaking with energy, passion and conviction.”

Axelrod even went to the extent of saying “a lot nervous” supporters of the former vice president were “walking with a little more verve” now.

The high, however, proved to be short lived. On Thursday, the 76-year-old Biden made three high-profile gaffes on the campaign trail that quickly renewed all of the old doubts about his candidacy.

The gaffes began innocuously enough, with Biden telling voters at the Iowa State Fair that “we choose truth over facts.”

“Everybody knows who Donald Trump is. Even his supporters know who he is. We got to let him know who we are. We choose unity over division,” Biden said towards the end of his stump speech. “We choose science over fiction. We choose truth over facts.”

Many of the those watching were left confused as to what Biden meant. As Breitbart News has reported, the comment was likely the result of Biden flubbing an applause line he frequently uses to end campaign appearances: “we have to choose hope over fear, unity over division and, maybe most importantly, truth over lies.”

Although the gaffe was widely panned on social media, it was only the beginning of what Biden had in store. Later in the evening, while addressing a town hall in Des Moines, Iowa, organized by the Asian and Latino Coalition, Biden confused the name of recently ousted British prime minister, Theresa May, with the late Margaret Thatcher – who left office in 1990.

“Words that stunned the nation, and I would argue – I know – shocked the world. International leaders spoke about it,” Biden said when falsely alleging Trump praised the neo-Nazis that marched on Charlottesville, Virginia in 2017 as “very fine people.”

“You had people like Margaret Thatch… excuse me,” the former vice president said catching himself. “You had people like the former chairman and the leader of the party in Germany. You had Angela Merkel stand up and say how terrible it was. International leaders looked at us like, ‘what in God’s name is happening to the United States of America?’”

The blunder, though, received little notice until Friday morning because the most notable portion of Biden’s speech also held his most embarrassing gaffe. While discussing his plans to reform America’s education system, Biden stated that “poor kids are just as bright and just as talented as white kids.”

“We should challenge these students, we should challenge students in these schools to have advanced placement programs in these schools,” the former vice president said. “We have this notion that somehow if you’re poor you cannot do it. Poor kids are just as bright and just as talented as white kids.”

Biden quickly tried to clarify, adding “wealthy kids, black kids, Asian kids” as an addendum to his last sentence. Despite efforts by the candidate and his team to walk back the racially insensitive remarks, the damage was done.

Even before the gaffes were fully understood, several prominent individuals on the left began questioning not only Biden’s capabilities as a candidate, but also his competence to be commander in chief.

One of the most vocal was Adam Jentleson, a one time deputy chief of staff to former Senate Minority Leader Harry Reid (D-NV). Shortly after the gaffes went viral on Thursday, Jentleson took to social media and called on Biden’s team to prove their candidate was up to the task of running for president.

“Biden and his team owe it to voters to put him run a real, rigorous public campaign schedule, like everyone else. If he can hack it, great. If not, better to know sooner rather than later,” he wrote. “Keeping him under wraps except for big events while trying to skate by is just sketchy.”

The sentiment was echoed by Ryan Grim, the Washington, D.C., bureau chief for The Intercept. Grim, himself, suggested Biden’s team would have to be “sociopathic” to try to install a candidate “not fully with it” in the Oval Office.

“Senior Biden advisers, if they’re trying to smuggle in a candidate who isn’t fully with it, are truly playing with fire,” Grim wrote. “That’s a sociopathic (and ultimately unsustainable) strategy if that’s what’s happening.”

Even though Grim and Jentleson are some of the first to voice these concerns publicly, others have been making them privately and anonymously for some time.

“I was worried after the first debate he might have lost a step,” a Democrat serving in the United State Senate told The Hill earlier this month while discussing Biden’s performance in the first presidential primary debate.