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.

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.