Democratic pollster Nancy Zdunkewicz said Friday that there are a group of moderate Republicans who say they would be willing to consider voting for a candidate like outgoing Ohio Gov. John Kasich (R) in a match-up against President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE.

"We've been polling a three-way race with Donald Trump and Kasich, and whoever the generic Democratic candidate for president would be, and there's a large part of the Republican Party, about 25 percent that are moderates, and they are very willing to consider voting for John Kasich," Zdunkewicz, managing director of Democracy Corps, told Hill.TV's Jamal Simmons on "What America's Thinking."

"In fact, about 20 percent of them are already defecting," she added.

Kasich, who ran against Trump in the Republican primary in 2016, has been floated as a potential challenger to the president for 2018.

The Ohio governor's spokesman, John Weaver, said Friday that Trump should be careful what he wishes for, in response to comments from the president, saying he hoped Kasich would challenge him.

However, a Hill.TV American Barometer poll released last month found that 67 percent of self-identified Republican respondents said they would vote for Trump when asked to choose between the president and Kasich.

— Julia Manchester