Pennsylvania is perhaps the most pivotal swing state up for grabs in this election, just like it was in 2020. But there have been some big changes in the state since last time at the registered voter level.
One reason why Republicans are optimistic about their chances to retake the state is Pennsylvania’s voter registration numbers: While there are still more registered Democrats than registered Republicans, in March 2021, there were 630,000 more registered Democrats than Republicans in Pennsylvania. In October 2024, this discrepancy was cut in half, now standing at around 300,000.
Several factors cause shifts in voter registration numbers. First, some existing registrations get removed from the rolls when those people die, move, or go too long without voting. Existing registrants also sometimes change their party of registration. Finally, new registrants are constantly being added to the rolls.
To better understand which of these factors is causing the Democratic registration edge to narrow in Pennsylvania, the NBC News Decision Desk merged together individual registrations from its voter database in March 2021 and October 2024 to track how registered voters were moving between parties and status.
The chart below illustrates all of the changes in registrants’ parties over this time period. Overall, it shows that there are about 110,000 fewer registered Democrats in 2024 than in 2021, and about 220,000 more registered Republicans.
Already registered voters changing their party has been the most consequential factor narrowing the Democratic registration edge. Over 160,000 people who were registered Democrats in 2021 are now registered Republicans.
Conversely, only 58,000 Republicans shifted their registration to Democratic during the same time period.
Moreover, another 83,000 people who were registered as Democrats in 2021 have switched to being unaffiliated with a major party. A little more than half of that number of previously registered Republicans — 50,000 — did the same.
Then, registration removals also contributed to narrowing the Democratic registration edge. There were about 430,000 Democrats in 2021 who are no longer registered in 2024, as compared to about 330,000 Republicans.
But new voter registrations have not played a role in the narrowing Democratic Party registration edge. In fact, slightly more people who have registered since 2021 are now registered Democrats than registered Republicans.
How might these changes affect the 2024 election? Looking specifically at voters who cast a ballot in the 2020 election could help answer that question.
Just looking at 2020 voters who have changed their party since then, about 130,000 registrants who were Democrats when they voted in 2020 are now registered Republicans.
Conversely, only 47,000 registrants who were Republicans when they voted in 2020 shifted to being registered Democrats.
More 2020 voters who were independents then have registered as Republicans than as Democrats. Finally, among 2020 voters who have since had their registrations removed, slightly more were Democratic registrants than Republican registrants.
Another big chunk of the narrowing gap between the parties in registration comes from registration removal of people who didn’t vote in 2020. About 240,000 nonvoting registration records of Democrats were removed, as compared to about 160,000 nonvoting registration records of Republicans. Party switching also plays a smaller role — 31,000 former Democrats turned Republican compared to 11,000 former Republicans who turned Democratic among the 2020 nonvoters who have switched since then.