Poll shows Pennsylvania GOP Senate primary remains tossup, after Trump's endorsement of OZ

A new poll shows Pennsylvania's GOP Senate primary remains a wide open race, following the endorsement of candidate Mehmet Oz by former President Donald Trump. 

The Monmouth University poll released Wednesday shows Oz and former hedge fund CEO David McCormick atop the primary candidate field, with conservative pundit Kathy Barnette close behind, despite being vastly outspent by her rivals.

Most GOP respondents said they were aware of Trump's endorsement, and 22% said it shifted their view of Oz to a more favorable position. However, Oz's unfavorable figure (37%) remains higher than McCormick's (15%). 

The retired celebrity physician and Fox News Channel personality has Trump's influential support. But some of his views on COVID-19 treatments and the 2020 election results have raise concerns within Republican circles about whether he can win the general election and retain the seat of retiring GOP Sen. Pat Toomey.

Trump's recent endorsement of "Hillbilly Elegy" author J.D. Vance in the Ohio GOP Senate primary, to keep retiring Republican Sen. Rob Portman's seat, almost immediately moved Vance from third to first in polling. 

Just under 50% of Republican primary voters say there is no candidate in the field they are "very likely" to support at this stage, also according to the poll. 

McCormick (16%), Oz (20%), and Barnette (12%) were the only Republican candidates to crack double-digit support on the question of who is best qualified to address voters' top concerns, which include inflation and illegal immigration.

"This is the kind of environment where a number of candidates could emerge as the nominee," Monmouth pollster Patrick Murray said. "Oz has the highest name recognition but also the highest negatives. If McCormick and Oz beat each other up, though, Barnette could realistically end up on top."

Murray said about the Trump endorsement: "If Dr. Oz thought Trump’s seal of approval was going to lock this nomination up for him, he was mistaken. It may help Oz on the margins, but it doesn’t completely erase his negatives."

In the Democratic primary, outcomes seem clearer, with Lt. Gov. John Fetterman in front with the highest name recognition (81%), a 68% favorability rating, and 44% of registered Democrats saying they are "very likely" to support him.