Democratic presidential hopefuls former U.S. Vice President Joe Biden stands alongside...

Democratic presidential hopefuls former U.S. Vice President Joe Biden stands alongside as U.S. Senator for Vermont Bernie Sanders speaks during the second Democratic primary debate of the 2020 presidential campaign season hosted by NBC News at the Adrienne Arsht Center for the Performing Arts in Miami, Florida, Thursday. Credit: AFP/Getty Images/SAUL LOEB

It wasn’t a good night in Miami for the two leading Democratic contenders for president. 

Former Vice President Joe Biden and Vermont Sen. Bernie Sanders came across as old — as veritable caricatures of themselves  — while two emerging political talents, South Bend Mayor Pete Buttigieg and California Sen. Kamala Harris, shined before a massive national audience.

They, and Wednesday night's debate victors, Massachusetts Sen. Elizabeth Warren, New Jersey Sen. Cory Booker and former HUD Secretary Julian Castro, should expect a major boost in fundraising and media attention in the weeks ahead.

That doesn’t mean post-debate polls will dramatically change. Biden will likely keep his lead — pluralities are all that count in 25-candidate races — and Sanders will probably maintain his base of supporters. But Warren may very well surpass Sanders in national polls next week, and Harris and Buttigieg should be hot on their tails. Castro should make it onto the low rungs of the viability ladder for the first time, too.

One thing is clear after the Miami debates: many candidates running don’t belong on a presidential stage. The Democratic National Committee should quietly usher them to the sidelines. They know who they are, or should. 

Harris probably had the best night Thursday. She excels as the prosecutor — she put Biden on the stand in Miami for his 1970s vote on federal bussing mandates — but her persona needs more, in this analyst's opinion anyway. It can’t be all prosecutor all the time. There has to be more of an emotional connection with voters.

Buttigieg again showed Thursday why he has wowed so many so quickly. He is an extraordinarily gifted communicator who locks in on points masterfully. His remarks are almost always well constructed and nuanced, and he has a natural ability to relay sincerity to an audience large or small. When questioned about the recent police shooting of a black man by a white police officer in his city, Buttigieg didn’t flinch. He took the question head on,  acknowledging that he hasn’t been able to integrate the South Bend Police Department quickly enough. I think he gets points for that.

Sen. Kirsten Gillibrand, like Mayor Bill de Blasio the night before, bared her sharp New York elbows Thursday, constantly interrupting other candidates for speaking time over the hopeless protests of the debate moderators. But when Gillibrand got her chance to speak, she didn’t have the goods. It was all platitudes and her talking points. (How many “comprehensive plans” can one have?) I would anticipate de Blasio gaining some traction in the next group of surveys after a good debate appearance Wednesday, and Gillibrand achieving virtually none.  

One interesting note about Biden: He was the only candidate on stage Thursday who wore an American flag lapel pin. I’m not sure what that means; I just thought it worth pointing out. 

Biden and Sanders had the most to gain and lose on Thursday, and neither fared well. Sanders was characteristically grouchy, and Biden, for the first time, seemed to have lost some velocity on his fastball. He’ll have to get his speed back up for the next round of debates in Detroit on July 30 and 31 because there are some talented candidates gunning for him.

The race has now begun. 

William F. B. O’Reilly is a consultant for Republicans.