Trump only won Pennsylvania by a plurality and without third party candidates it's possible he wouldn't have won at all. The difference between Pennsylvania and Ohio is that Pennsylvania has metro areas that can outvote the rural areas. Mastriano is a horrible fit for suburban Phildelphia and to an extent the increasingly Democratic trending suburbs in Allegheny County.
Then why did Mitt Romney who is a great fit for the suburbs of Philly and even won Chester county get his ass kicked there in 2012? Even in a losing effort in 2020 Trump barely lost the state in an unfavorable year to the GOP while getting slaughtered in the Philly suburbs.
Here is the correct answer:
Pennsylvania is a balancing act, you have to balance the right amount suburban support with a substantial amount of working class support to get over the top.
Bush was too heavily leaned into religious suburban conservatism and while he held up okay in the West, he got destroyed in the more secular Philly Burbs, and his abandonment of the trade war, and lack of any great recovery in manufacturing prevented enough of a working class swing to offset the lost in secular suburbs (he narrowly lost the Lehigh valley, Lost Luzerne, Lost Erie etc).
Romney also had the wrong mix to be able to win the state. Romney really did not use any of the available economic wedges that he had except for Coal, but Coal is only really a factor in "the West" (Pittsburgh Area and counties bordering OH and WV). This meant that he left votes on the table in places like Erie, Luzerne county, and the Lehigh Valley where coal alone wasn't going to do it because coal was never a factor or had not been a factor since the 50s (like Scranton).
Trump hammered immigration and trade hard, he turned historical swing Luzerne County (a county that as of 2010 was a top 4 bellwether county for the state) and turned it into a 20% Republican margin. This is because as the presence of migrant labor has increased in rural PA, there has been an hostile reaction among the historical Democratic, non-college whites in these small and medium towns like Hazelton (Lou Barletta was Mayor of Hazelton).
Romney dialed back the immigration rhetoric in the general and gained nothing for it but all of the negatives for how he ran on it in the primary. Honestly, Romney should have gone hardline on immigration in the general election.
He also embraced Paul Ryan, whose economic agenda was already a proven disaster among even working class ancestral Republicans (NY-26 special in 2011) and certainly wasn't going to win any favors with working class Hispanics, regardless of some silence on the immigration issue. He also failed to hammer the Chinese currency manipulation issue, which he had earned Donald Trump's endorsement on (not kidding).
By contrast, Trump started every speech with "This is how many factories you have lost since Bill Clinton signed NAFTA, here is how many manufacturing jobs you have lost since China was admitted to the WTO" and he spent two years doing that almost.
It shows in the results, Romney lost Luzern by 5% and Lackawanna by 27%. Trump won Luzerne by 19% and lost Lackawanna by 3%
Yes, you can win PA with a suburbs focused, conservative campaign but you need to do much better with working class non-college whites (of non-Yankee/German ethnic background) in the West, the NW (Erie), the NE (Scranton-Wilkes-Barre-Hazelton - My former neck of the woods) and the Lehigh Valley (Allentown), than what Romney was able to pull off.
Pat Toomey, is by ideology and personal positions on these issues, a horrendous fit for these voters. But Toomey had sense enough to accrue a solid rating from NumbersUSA in the 1990s, he voted against the 2013 Immigration Bill even if his justification (not enough legal immigration in the bill was horrendous for these voters once again) and ran hard against sanctuary cities in 2016. Toomey didn't do as well in Luzerne as Trump, but he still won it by 8% and lost Lackawanna by 13%. He won Bucks by 5% and Chester by 2%, Northampton by 6%, Dauphin (Harrisburg) by 1%, and Erie by 3%.
For a "pro-business" Republicanism, to win in the rust belt it is going to have to take a page out of the 19th century and go far more nationalist on trade and immigration, which was the mix that 19th century Republicans used to keep PA as a Republican state until the Depression. It is a mix that they they, the donors and the establishment just are not use to because it is just different in the South where other wedge issues boost the support with non-college whites enough to win (God, Guns, Gays in the 1990s for example).
