If past is prologue, President Trump will win Pennsylvania.

Eight years ago this week, Senator Clinton led in Pennsylvania by more than nine points; four years ago, President Biden led by nearly six points. Mrs. Clinton lost Pennsylvania by less than a point, while Mr. Biden won it by more than a point.

Heading into the Democratic National Convention, the Emerson/RealClearPennsylvania poll showed President Trump leading Vice President Harris by a point.

Averaging together the Pennsylvania polling taken since Ms. Harris became the Democratic Party’s nominee, the state’s presidential race is a dead heat.

Of the 59 public polls released in 2016 tracking the Pennsylvania presidential race, Trump led in only two. In 2020, Trump led in only five of the 84 Pennsylvania polls released.

This cycle, Trump has led in 13 of the 17 Pennsylvania polls released. Trump is leading more polls than the previous two election cycles combined, and we have yet to reach Labor Day, when polling frequency intensifies.

Considering the previous Pennsylvania election results, today’s polling suggests that Trump is poised to seize the largest margin of victory for a presidential candidate in Pennsylvania since President Obama’s eight-point win in 2008.

It’s unlikely that Trump can duplicate Mr. Obama’s margin. Pennsylvania voters are supremely polarized, just like elsewhere in the country. The partisan mobilization of the left and right guarantees a close race. Ms. Harris’s candidacy has ignited a previously dormant liberal base, while legal persecution and an assassination attempt on Trump crystallized voting as a cultural imperative on the right.

Nonetheless, the dramatic polling shift compared with previous presidential election cycles is confounding, as no pivotal factor explains Trump’s persistent overperformance. Rather, it appears to be caused by an accrual of factors.

One factor may be the reputed “shy Trump voters” who are no longer inhibited from voicing their support. These voters shocked the world in 2016 and defied 2020 polling. They are now out of the Trump closet, loud and proud.

Another factor may be the strength of regional biases. In northeastern Pennsylvania, Mr. Biden wore his “Scranton Joe” moniker proudly, emphasizing his birthplace and hardscrabble roots in the Commonwealth. It helped Mr. Biden tap into the region’s swing voters in a way that Mrs. Clinton could not. Now these voters are trending Republican, and Mr. Biden’s absence from the ticket gives license for them to go with the GOP.

It’s a similar dynamic in northwestern Pennsylvania. Erie County’s working-class voters, who put both Mr. Obama and Trump in office, are unlikely to lean toward Ms. Harris, who calls San Francisco home. In Butler County, where Trump was shot and a beloved firefighter was murdered in the crossfire, voters will surge for Trump to a historic level.

In the Philadelphia press market, which includes Delaware, daily political coverage included Mr. Biden’s senatorial career for more than 40 years. Philadelphia and suburban residents learned about Mr. Biden’s doings no differently than from their own senators. Mr. Biden improved on Mrs. Clinton’s historic suburban margins; Ms. Harris cannot recreate this affinity.

An African-American turnout surge at Philadelphia and Pittsburgh, akin to that which propelled Mr. Obama into office, is highly likely. However, the anecdotes of Trump getting a closer look from Black males are real. He earned 12 percent of the Black vote in 2020, and it is not unreasonable to expect that he could maintain or improve on that performance, which may negate a Harris-driven turnout surge.

Driving the wedge with African American males, and with most Pennsylvanians, is the economy. More than 50 percent of Pennsylvanians rank the economy as the top issue, with Trump carrying a commanding lead over Ms. Harris in this regard. Meanwhile, less than 5 percent of voters rate abortion access as the election’s top issue. Most Pennsylvania political analysts cannot recall a time this century when a single issue so dominated voters’ priorities.

The unprecedented shift in Pennsylvania’s voter registration is yet another factor. Since 2008, the 1.1 million-voter Democratic registration advantage has whittled down to about 350,000. Prior to the 2024 Pennsylvania primary, all 67 of Pennsylvania’s counties saw net gains of Republican voters. Should the trend continue, Pennsylvania will be majority Republican by 2028.

Mail-in balloting is relatively new to Pennsylvania. Starting during the 2020 Covid lockdowns, Democratic applicants hold a nearly three-to-one advantage over Republicans. While the margin is daunting, the lack of enthusiasm for Mr. Biden’s candidacy may hold relief for Republicans. 

In the 2020 presidential election, nearly 1.7 million Democrats applied for a mail-in ballot; more than half of applicants applied after the third week of August. In the 2022 midterm, more than 900,000 Democrats applied for a mail-in ballot; about one-third applied after the same week in August. 

This year, about 650,000 Democrats have applied as of last week. To meet 2020’s tally, the Democrats have a lot of work to do. Yet all these factors pale beside the stunning polling trend that Trump is experiencing in the Keystone State. The former president’s Pennsylvania polling strength and consistency may be the most underreported trend of the 2024 election cycle.

This article was originally published by RealClearPennsylvania and made available via RealClearWire.