If it all comes down to Pennsylvania, we end up in loads of legal battles, which ultimately comes down to the newly Republican weighted Supreme Court.
I’d be more worried about Wisconsin, looking at the BBC’s online infographic (not sure how up to date it is) it’s showing 99% counted with Biden ahead, but by less than 1%, Which would allow trump to demand a recount, correct?
Pennsylvania is arguably less marginal than Wisconsin…
As for the Supreme court, as I understand it (IANAL) that would be the very final resort for trump, he would have to challenge the validity of specific state(s) polling and/or counts, with actual verifiable evidence (not just claims) first at the individual state level, before going to the US appeals court. By the time he actually got to the supreme court he’d have had the same case ruled against twice en-route, at which point a different ruling would look very suspect and seriously undermine the supreme court’s independence, opening them to very similar claims of nepotism and conspiracy, so they may well have to find against him… He might have tried to stack it in his favour but that very decision could have actually limited his options…
Trumps best (only?) chances now sit with demanding recounts in the most marginal states