Sanders responded: «Hey Mr. Putin, if I’m president of the United States, trust me you’re not going to interfere in any more American elections.»

The new wave of infighting came as Democrats met for the party’s 10th — and perhaps most consequential — debate of the 2020 primary season. Tuesday’s forum came just four days before South Carolina’s first-in-the-South primary and one week before more than a dozen states vote on Super Tuesday.

The former New York City mayor was the focus last week for his highly anticipated debut, but after a bad performance that froze his momentum, the knives were out for the 78-year-old Vermont senator.

Former vice-president Joe Biden went after Sanders for what he characterized as softness toward gun-makers, saying Sanders’s position «has caused carnage on our streets.»

Sanders, in 2005, supported a proposal backed by the National Rifle Association granting gun manufacturers broad legal protections. He has repeatedly been put on the defensive during the 2020 campaign on his perceived support for the gun manufacturing industry.

On Tuesday, Sanders responded he has «cast thousands of votes, including bad votes. That was a bad vote.»

Pete Buttigieg also took on Sanders, saying his position on guns wasn’t an old one but «is a current bad position that Bernie Sanders holds.»

Tuesday night marked a major moment in Sanders’ political career. After spending decades as an outside agitator accustomed to attacking the party establishment, he’s suddenly the one on defence as the Democratic establishment fears he could build an insurmountable delegate lead as soon as next week.

Warren ‘dug in’

Elizabeth Warren went straight at Sanders, a fellow progressive, saying she would be a better president than him because she’ll be able to get more progressive policies passed. The Massachusetts senator said she’s «dug in» when it comes to fighting big banks and actually explaining how she’d enact universal health care.

Warren said: «Progressives have got one shot, and we need to spend it with a leader who is going to get something done.»

Warren and Sanders share many of the same policy goals. But Sanders has performed far better in the early presidential nominating contests.

Her comments mark some of the sharpest contrasts she’s drawn with him so far. Sanders’ opponents have argued that he’s been ineffective during his three decades in Congress.

Warren also slammed Bloomberg over a news report that he told a female employee to «kill it» when she became pregnant.

Bloomberg denied making the remark. «Never said it, period. End of story,» he said.

Invoking her own story of discrimination on the job after she became pregnant, Warren escalated her push to get Bloomberg to release all former employees from nondisclosure agreements (NDAs) they signed while working at his media company.

Bloomberg apologized for other off-colour remarks he is reported to have made to female employees, but has declined to address Warren’s call to release more than the three women he previously released from their NDAs.

Race heating up

Biden was also looking to make a big impression in South Carolina, where he was long viewed as the unquestioned front-runner because of his support from black voters.

Also a factor: Billionaire activist Tom Steyer, who has borrowed heavily from his personal fortune to fuel a strong push in South Carolina, where he’s threatening to peel away some of Biden’s support with state’s black voters. Rivals Buttigieg and Amy Klobuchar are also fighting to win over moderates while decrying Sanders’ chief policy priorities.

Sanders’ handling of the pressure could be crucial in determining whether he stays at the top of the Democratic pack.

Heading into Saturday’s primary in South Carolina, Sanders has earned an estimated 45 delegates, according to 270ToWin, a non-partisan U.S. political website. Buttigieg sits in second with 26, followed by Biden, Warren and Klobuchar.

Bloomberg was not on the ticket for the first three nomination contests, as well as the upcoming primary in South Carolina, as he chose to focus his efforts on the 15 primaries and caucuses taking place on March 3 — popularly known as Super Tuesday.

During the primaries and caucuses, candidates compete for 3,979 pledged delegates who will vote for them at the Democratic National Convention in Milwaukee on July 13-16. If a candidate secures a majority of 1,990 pledged delegates or higher, he or she will have the necessary support to secure the Democratic nomination on the first ballot in Milwaukee.