'She owned the stage' — pollster says Kamala Harris was the winner of both Democratic debate nights

Key Points
  • Sen. Kamala Harris outshined all of her 19 rivals in the first Democratic presidential debates, says longtime GOP insider Frank Luntz.
  • "That was a brilliant debate performance," Luntz says of Harris.
  • At this point, it's all about convincing primary voters in key early-voting states such as Iowa, New Hampshire and South Carolina, he says.
Pollster Frank Luntz breaks down day two of the Dem debates

Sen. Kamala Harris outshined all of her 19 rivals in the first Democratic presidential debates, a longtime Republican pollster told CNBC on Friday.

"She owned the stage, and Joe Biden should have known it was coming," Frank Luntz said in a "Squawk Box" interview the morning after the second round of debates by Democratic presidential hopefuls.

Harris, a first-term U.S. senator and former California attorney general, came out swinging Thursday night, with pointed attacks on frontrunner Joe Biden. She called out the 76-year-old former vice president on race, saying the way he recently described his past working relationship with two segregationist lawmakers was "hurtful."

The 54-year-old Harris, if elected, would be the second biracial president. Former President Barack Obama was the first. Harris' parents were both immigrants — her father from Jamaica and her mother from India. They met as graduate students at the University of California, Berkeley.

At Thursday night's debate, Harris also accused Biden of opposing busing, which Biden disputed.

"There was a little girl in California who was part of the second class to integrate her public schools, and she was bused to school every day, and that little girl was me," Harris said.

Biden called Harris' attack "a mischaracterization of my position across the board," and launched into a fiery defense of his record on race. "I did not praise racists."

Sen. Kamala Harris (D-CA) speaks during the second night of the first Democratic presidential debate on June 27, 2019 in Miami, Florida.
Drew Angerer | Getty Images

"That was a brilliant debate performance," Luntz said of Harris. "She's the winner of both nights."

The 10 Democratic candidates on stage in Miami on Thursday night, which also included Sens. Bernie Sanders and Kirsten Gillibrand, went after President Donald Trump more aggressively than the 10 Democratic hopefuls from the first round on Wednesday night.

"Don't focus on the national numbers," said Luntz, who refused to say which Democratic candidate would present the toughest challenge to Trump's reelection campaign.

At this point, it's all about convincing primary voters in key early-voting states, the pollster said. "What really matters is Iowa, New Hampshire, South Carolina."

In handicapping Harris' primary chances, Luntz said, "South Carolina is 40% African American, the Democratic primary. She has now staked a clear claim to that vote. A number of them have been supporting Biden up to this point."