San Jose Mayor Sam Liccardo kicked off the event, he endorsed the New York City Mayor in January.
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"What Mike has shown as the mayor of the most complex most diverse big city in the country is that he can get things done," he said.
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Many in the room wore"I like Mike" buttons claiming he's the only one who can unseat the President.
"We're going to need someone who's strong who can take on Trump, who has the resources to run a very efficient 50 state campaign," said former Assemblymember Joan Buchanan.
At Manny's restaurant in San Francisco, Democrats supporting different candidates also gathered for a watch party. Some were less impressed with Bloomberg's debate debut.
"Not super well to be honest. I think that a lot of the candidates seeing that it was hit first time on stage with him have been attacking him pretty personally," said Cindy Li.
"So if I were to pick my three, I would say it has been Pete Buttigieg, definitely Elizabeth Warren and I think Joe Biden is making a comeback," said Robert Diaz Gonzalez.
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Back at Bloomberg's watch party, the loudest cheer happened when the former NY mayor said, "We tried communism and it just didn't work" hitting back at his fellow candidates' plans on health care and taxes."
"I do agree with those who say that Bernie being a Democratic socialist is going to be a problem," said Buchanan.
But for some at Manny's, it's Bloomberg's performance that's a problem.
"Personally, I am not incredibly impressed but I think he is definitely keeping it lively," said Morgan Linton.
"I would say that right now, he hasn't pulled out his knives just yet because he's saving that for Donald Trump," said Lu See Kwik.