PHILADELPHIA • There’s something about Pennsylvania’s political DNA that’s playing out in this year’s crucial Senate race.

It’s not that we have one unifying statewide identity, but we are a state with lots of intense regional identities — that can oftentimes breed distrust of out-of-towners.

People don’t say they’re from Pennsylvania. They say Pittsburgh or Philly; NEPA or the Lehigh Valley; western Pa. or Johnstown; the Philly burbs or Delco. The dividing lines aren’t along our state borders but east vs. west, Wawa vs. Sheetz, city vs. rural, Steelers Nation vs. “Go Birds” and Philly vs. Everybody.

And it’s amid this brand of parochialism that Mehmet Oz has struggled to quiet an onslaught of attacks about his Pennsylvania ties. Oz, a celebrity doctor who moved here from New Jersey to run for the seat, was likely always going to face challenges appealing to everyday Pennsylvanians, campaign strategists, former politicians and political scientists say, but something about Pennsylvania’s ethos seems to be making it even harder.

“Every single thing about our state promotes local identity,” said Ben Forstate, a Democratic political analyst from western Pennsylvania, more specifically, Allegheny County, more specifically Pittsburgh, and more specifically the North Hills neighborhood.

The state is carved up into tiny townships, municipalities, and school districts, all with unique tax laws and individual character.

“You vote for everything, you expect your politicians to be accessible,” Forstate said. “We like people from our own regions. We’re suspicious of people from other regions. We don’t like outsiders . ... Pennsylvania doesn’t have a positive personal identity, but we definitely have a negative one, and that’s where Dr. Oz is provoking some sort of weird immune response.”

Pennsylvania doesn’t have one state fair but dozens of county-based ones. We list the home counties of candidates right there on the ballot next to their name — and those hometowns have ended up swaying elections. And while every state has some degree of hometown pride, perhaps most notably, Pennsylvania ranks fourth in states with the most residents who were born where they live.

That hyper-regionalism could be why the carpetbagging attacks against Oz resonate. In social media posts, banner planes, billboards and via New Jersey celebrities, Lt. Gov. John Fetterman has relentlessly shouted the same message at voters: Oz isn’t from here.

At the same time, Fetterman’s branded himself as a Pennsylvania everyman, dressed in shorts and a hoodie, whose latest campaign ad proclaimed he has “Pennsylvania in his blood.” Pennsylvania is not New York Oz, who grew up in Delaware and went to medical and business school at the University of Pennsylvania, has started crisscrossing the state to campaign. But he’s struggled to shake the “outsider” label.

In a late July poll, 37% of voters said they were extremely concerned Oz “may not be familiar enough with the state of Pennsylvania to carry out the job of senator effectively.” An additional 34% were somewhat or very concerned.

“Pennsylvania is Dr. Oz’s home,” campaign spokesperson Brittany Yanick said. “He grew up in the Greater Philadelphia region, went to school in Pennsylvania, met his wife and got married in Pennsylvania, and currently resides in Bryn Athyn, where his wife’s family has lived for a hundred years.”

Former Gov. Ed Rendell, who was born in the Riverdale section of the Bronx but now lives in the East Falls section of Philadelphia, recalled running for reelection in the late 1990s and being blasted for not being from the state.

“I’d lived here for 30 years,” he said.

He thinks any candidate moving into Pennsylvania might encounter similar issues.

“I think because we’re located between New York and Washington, it builds up a little bit of an inferiority complex, which breeds parochialism,” Rendell said. “We don’t like to be used, no matter who it is. We wouldn’t like to be used by Hillary [Clinton] or Bobby [Kennedy] or Mehmet Oz.” (Clinton and Kennedy both famously relocated to New York to run for Senate seats there.