Pennsylvania, the Keystone State, is likely to be the keystone state in the election, and where it ranks will likely depend on which areas have the most voters.
Democrats have long relied on boosting their vote share in the state's cities, including Philadelphia and Pittsburgh, of course, but also mid-size cities where Democrats win by large margins: Scranton, Harrisburg, Allentown, Bethlehem, Erie and Wilkes-Barre are just as important to a Democratic chance of victory as the two largest cities.
Democrats' chances could be tougher this year because Donald Trump is performing relatively well among minority voters. These and other smaller areas have significant numbers of blacks, Latinos or both.
Trump has performed better among these groups in 2020 than he did in 2016, with polls showing the former president performing several points better in 2020. Narrowing the vote margin in Democratic strongholds would significantly improve Trump's chances of victory.
That's because Trump is expected to win most of the rest of the state.
Bill Clinton's 1992 campaign manager, James Carville, famously joked that Pennsylvania was made up of Philadelphia and Pittsburgh, with Alabama in between.
While this overstates the region's Republican leanings, the area between the two cities remains a huge swath of Republican votes.
These areas are also the heartland of the blue-collar Obama-Trump voters who have supported Trump's rise to power.
Luzerne County, in the northeastern corner of the state, is a case in point.
Barack Obama beat the aristocrat Mitt Romney by five points, while Trump beat Hillary Clinton by 19 points.
Even “Scranton Joe” Biden was able to narrow Trump's lead to 14 points. Since then, Republicans have continued to gain ground. Looks like I'll pass For the first time in decades, Democrats were on the voter registration rolls by Election Day.
The story is similar across the state: In November 2020, Democrats had a 685,000-member lead over Republicans in registered voters. That dropped to 396,000 by the time of this April's primary and has since lost another 46,000.
Interestingly, a lot of this is driven by party changes.
Between 2021 and 2023, roughly 75,000 more Republicans and independents switched their party registration to the Republican Party than switched to the Democratic Party among Republicans and independents. Republicans have gained roughly 25,000 more registrations so far this year.
Both trends point to positive results for Trump, but they are offset by the former president's continued weakness in the state's more educated suburban areas.
This trend is particularly evident in the Philadelphia suburbs of Bucks, Chester, Delaware and Montgomery counties, and is a key reason why Vice President Kamala Harris still has a chance of winning the state.
Chester, Pennsylvania's best-educated and wealthiest county, is a prime example of this movement: Mitt Romney narrowly won it in 2012, but Clinton won it by more than nine points.
Biden turned that into a 17-point victory. Trump narrowly lost the state in 2020 because of similar dramatic shifts in other well-educated communities.
How each candidate performs in each region will determine who wins.
Harris will need to continue to see strong voter turnout and vote share from her traditional urban base, as well as big wins in upper-class white suburban areas.
Trump needs to regain his 2016 support in Pennsylvania's rural and small towns while chipping away at Harris' support in the city and affluent suburbs.
Two counties on opposite ends of the state will provide early clues on election night.
Erie County and Northampton are bellwether counties that tend to swing the outcome in close elections: Trump won both in 2016 and lost both in 2020. If Trump wins both counties again, it would bode well for the campaign.
One reason is that a win here would open many paths to winning the 270 electoral votes.
If he wins Pennsylvania's 19 electoral votes and all the states he won in 2020, he only needs 15 more to take the White House. He could get those 15 votes by winning either Georgia or Michigan, or by winning Arizona or Wisconsin and Nevada, or by winning only Arizona and Wisconsin and losing the others.
That means Pennsylvania is not just a cornerstone for Trump, it's a gateway to victory.
Astute observers will be keeping an eye on where the campaign visits over the next two months.
Trump and his running mate, J.D. Vance, are expected to launch an aggressive rural offensive, but will they spend much of their time courting wealthy suburbanites and urban minorities?
Harris will likely spend a lot of time in cities and suburbs trying to hold onto the Biden coalition, but will she and Tim Walz spend time wooing blue-collar white people elsewhere?
It is too early to say who will win this political trench war.
What is certain is that how each side views the state's three regions will play a big role in determining who wins.
