The playbook that Republicans could put to use in Pennsylvania this year was partially developed in 2000, in the aftermath of the Presidential race between George W. Bush and Al Gore. That year, the election was close, and the contest came down to Florida, where the candidates were separated by only a few hundred votes. After the initial count, a swarm of attorneys and poll watchers descended on the state to catalogue small mishaps that might serve as grounds to challenge the results. Most notably, they found that some voters had failed to fully perforate their punch-card ballots, creating what came to be known as “hanging chads.” Legal disputes about whether to continue tallying ballots, and which to count, wound their way to the Supreme Court, which eventually halted further recounts, leaving Bush in the lead. Gore conceded on December 13, 2000. But, even if the Supreme Court hadn’t intervened, Gore still might have lost the state. In Tallahassee, the Republican legislature had already begun the process of choosing a set of Republican electors who were going to vote for Bush regardless. This year, Wisconsin, North Carolina, and Michigan all have conditions that would allow for such an eventuality. (G.O.P. lawmakers around the country have denied any such plans. Andrew Hitt, the G.O.P. chair in Wisconsin, recently said that he’d heard of “no such discussion.”) But Pennsylvania seems most vulnerable. “Harrisburg in 2020 could be Tallahassee in 2000,” Ari Mittleman, a political analyst with Keep Our Republic, told me.