US election: Joe Biden mixes up wife and sister on Super Tuesday

US presidential candidate Joe Biden claimed frontrunner status in the Democratic race after pulling off a surprising political recovery on Super Tuesday. 

The 77-year-old is now the favourite to win the Democratic nomination after notching up wins in nine states during 'Super Tuesday', in which 14 states hold primary elections and caucuses. 

Yet the former Vice President's victory speech was trumped by another of his now predictable blunders, this time confusing his wife, Jill Biden, for his sister Valerie.

"By the way, that's my little sister Valerie, and I'm Jill's husband... oh no, you switched on me! This is my wife, this is my sister - they switched on me!" the 77-year-old exclaimed as the women laughed off the gaffe.

US political commentator Danielle McLaughlin said the two women switched places, leading to the confusion.

"They did switch on him, they were standing behind him... they had actually switched positions," McLaughlin told The AM Show on Thursday.

"He has a well-established and long-held issue with stuttering, we all know about the 'Biden gaffes', there's no hiding that.

"He's coming up against a President who often makes misspellings in tweets and is not a polished performer, and people love Trump for that. I think there is something to be said for being authentic and a little bit unpolished."

Although Biden won in crucial states Texas and Massachusetts, Democratic rival Bernie Sanders took very lucrative California. Meanwhile, it appears to be the end of the line for Elizabeth Warren, while former New York Mayor Michael Bloomberg has dropped out of the race, endorsing Biden.

McLaughlin says many Americans are betting on Biden.

"Not because of his policies, but because they think he can beat Donald Trump."

In 2017, gaffe-prone Biden was blasted for making comments about children "jumping on his lap" when he worked as a lifeguard. 

"I sit on the stand and it'd get hot... I got hairy legs... and the kids used to come up and reach in the pool and rub my leg down so it was straight and then watch the hair come back up again," Biden said during a speech.

"So I learned about roaches and I learned about kids jumping on my lap... I love kids jumping on my lap."

The politician has also faced accusations of unwanted physical contact from numerous women.