PHILADELPHIA — As the national early vote climbs past a staggering 93 million and challenges to the electoral process intensify across states, President Trump and Joseph R. Biden Jr. are barreling into Pennsylvania and turning it into the top battleground in Tuesday’s election, with Democrats flooding in with door-knockers and Republicans trying to parlay Mr. Trump’s rallies into big turnout once again.
Both campaigns see Pennsylvania as increasingly crucial to victory: Mr. Trump now appears more competitive here than in Michigan and Wisconsin, two other key northern states he…
