For Republicans, the question is whether Mr. Trump’s army of devoted voters comes out to support candidates who have modeled themselves in his image — even when he is not on the ticket.
So far, turnout has kept pace with the record levels of 2018, the first midterm election after Mr. Trump took over the nation’s political consciousness. But strategists on both sides acknowledge that the extraordinary circumstances of this year’s elections, the first since the pandemic began to wane, leave them unsure about who, exactly, will vote.
“We know that for better or worse, ever since Trump came into the scene in 2016, voters are supercharged,” said Molly Murphy, a Democratic pollster and strategist and the president of Impact Research. “But how much of the Trump core shows up is an open question.”
Pennsylvania has emerged as a central focus of both parties, with a narrow Senate race between Mr. Fetterman and Dr. Oz that could decide control of the chamber. In the House, where Republicans need to flip just five seats nationwide to gain power, the party could flip three from Democrats in Pennsylvania alone. And in 2024, Pennsylvania is likely to reprise its crucial role in determining presidential elections.
The state, where television viewers have been targeted with $115 million in political advertising over the past month, captures some of the country’s main tensions, with college-educated liberals concentrated in urban and suburban areas squaring off against blue-collar workers with shifting party loyalties. With their events in the state’s two biggest cities, Mr. Biden and Mr. Obama will potentially reach nearly a quarter of Pennsylvania’s active Democratic voters.
“Inside the confines of the commonwealth, you can find every political tribe in America represented in a big way,” said David Urban, a Republican strategist and a veteran of Pennsylvania politics.
The state has about 420,000 Republicans — about as many as in Arizona, Georgia and Nevada combined — who voted for the first time in 2016, did not cast a ballot in 2018, and then showed up to the polls again in 2020, according to Republican National Committee data. Only about 6 percent of those Pennsylvanians have cast ballots so far this year.