"I haven't seen anything like this": GOP pollster says Harris took massive "advantage" from Trump

Veteran GOP pollster and political strategist Frank Luntz told CNBC's "Squawk Box" on Wednesday that Vice President Kamala Harris, riding a surge of enthusiasm surrounding her candidacy and bringing in people uninterested in supporting either former president Donald Trump or President Joe Biden, has changed the pool of voters who will decide the November election. If trends continue in this direction, Luntz suggested, Democrats may not only win the presidency and retake the House, but also cling on to the Senate despite a lopsided map that favors Republicans.

"The people who were undecided have all collapsed towards Harris. The people who were weak Trump have all collapsed towards undecided. It's a broad shift," Luntz explained. The previously disenchanted voters Harris is adding to her coalition might not amount to more than a one- or two-percent change in the electoral pool. But that's enough to tip the election for Harris, he said.

Recent polls show Harris now tied or leading Trump in most battleground states, a swift and dramatic reversal in fortune from the closing weeks of Biden's struggling campaign. Luntz, wary of potential inaccuracies and undercounting of Trump supporters, has also relied on voter focus groups to understand the thoughts and feelings behind shifts in polling. Now, they're being "broken up by young women saying 'I'm not voting for [Trump] anymore.'"

"I'm trying to do a focus group tonight with undecided voters under the age of 27 for a major news outlet, and I can't recruit young women to this because they don't exist as undecided voters," Luntz said.

The increasingly dismal situation for Trump was no given; according to Luntz, Harris is surging against electoral headwinds, not with them.

"The issues and conditions favor Donald Trump. He should be winning this election. But the attributes are so much in Harris' favor that he's not," he said, pointing to Trump publicly backing Elon Musk's decision to fire striking workers as an example of the former president needlessly alienating the same voters he's been trying to poach from the Democratic coalition. "It's as though he's lost control. And I know there are billionaires who watch this show who are spending a lot of money on Donald Trump, and they don't understand why he's committing political suicide."

Meanwhile, Harris is still enjoying the momentum that has been building since she entered the race in late July. "She's got an intensity advantage. She's got a demographic advantage," Luntz said. "And I haven't seen anything like this happen in 30 days in my lifetime."