In sum, the Trump campaign’s fraud allegation is more theoretically aimed at the system of voting than concretely aimed at demonstrating the fraudulence of any particular ballot. But it is not entirely theoretical; Giuliani produced three witnesses who raise disturbing questions about the process, and he says he could produce over 50 such witnesses. He also says the derelictions occurred in other states — he explicitly mentioned Georgia, Michigan, and North Carolina at the press conference.
Plainly, the Trump strategy is: (a) cast sufficient doubt on hundreds of thousands of Philadelphia and Pittsburgh mail-in ballots that the courts order a recanvass which is closely scrutinized; and (b) continue prodding the Supreme Court to invalidate however many thousands of ballots arrived late — i.e., were received under the state court’s three-day extension, which countermanded the 8 p.m. Election Day deadline set by the state legislature (the body constitutionally empowered to set voting rules). The Trump campaign needs to knock out over 46,000 Biden votes, and surmises that the vast majority of these two buckets of ballots will be Biden votes — most of the votes come from urban Democratic strongholds; plus, Biden supporters were enthusiastically encouraged to vote by mail, whereas Trump urged supporters to vote in-person.
I suspect the lawsuits will not get traction if state officials can demonstrate that the actual counting of ballots at the county level was a bipartisan process in which Republicans meaningfully participated, and if they produce credible poll-watcher witnesses of their own to rebut the claims of the GOP poll-watchers. If the president fails to get traction in Pennsylvania, it would be time to concede to presumptive President-elect Biden. Pennsylvania is not sufficient for Trump to pull the proverbial rabbit out of the hat; but it is necessary.