Democrats’ voter registration advantage has dropped in three key battleground states — Pennsylvania, North Carolina and Nevada — raising a red flag for Vice President Harris as experts cite a lack of enthusiasm for the Biden administration brand and the Democratic Party, generally, as problems.

In Arizona, another key battleground state, Republicans have seen their voter registration advantage increase substantially, which could make it tougher for Harris to carry a state President Biden narrowly won in 2020.

Other presidential battleground states, including Georgia, Michigan and Wisconsin, do not register voters by party. 

The shift in voter registration away from Democrats in Pennsylvania and North Carolina may explain why the Harris campaign has tacked to the center on issues such as fracking and tax policy.

In Nevada, Democrats have seen their voter registration advantage drop, though Harris, unlike those other states, maintains a clear lead over former President Trump in the polling averages.

“If you look at the changes from 2020 to 2024, Democrats are down about 300,000 voters and Republicans are up about 70,000. Nonaffiliated independent voters are up about 83,000, 85,000 voters,” said Berwood Yost, director of the Center for Opinion Research at Franklin & Marshall College in Pennsylvania.

He said declining Democratic voter registration in some parts of Pennsylvania is driven by “disenchantment with the party in power Washington.”

“People feel really negatively about the Biden presidency,” he added. “Yeah, it’s a red flag, and they’re trying to fix it.

Yost warned that declining Democratic voter registration is a challenge for Harris in swing counties, such as Erie, North Hampton and Bucks, and in rural areas where she wants to keep Trump’s margin of victory as small as possible, such as Fayette County.

“It’s definitely a warning sign, but we knew this was going to be a close race. This is another example of that,” he said.

The Hill/Decision Desk HQ’s analysis of recent polls in Pennsylvania show Harris leading Trump by 1 point in the Keystone State but projects that both candidates have an equal probability of winning it.

David Paleologos, the director of the Political Research Center at Suffolk University in Boston, said Democrats had about a 666,000-person voter registration advantage over Republicans in Pennsylvania in 2020, which has shrunk to a 354,000-person advantage in 2024.

He said the Democrats’ voter registration advantage in North Carolina has shrunk from 393,000 voters in 2020 to approximately 130,000 voters in 2024.

“The general shift has been away from being registered as a Democrat over the last four years,” Paleologos told The Hill.

“It’s been more of a decrease of registered Democrats” than a surge in Republican voter registrations, he explained.

“I don’t think a lot of people have really put their arms around the fact that when Trump won North Carolina in 2020, there were like 390,000 more registered Democrats and he still won, and today the advantage of Democrats over Republicans is only like 130,000. It’s been cut by two-thirds of an advantage,” he said.

“Despite any gains that Harris may have made or microtargeting she may have done … Trump looks positioned to maybe widen what some of the polls are showing in North Carolina,” Paleologos observed of the Tar Heel State.

Lara Putnam, a historian at the University of Pittsburgh who studies election data, said older Democrats are dying out in Pennsylvania, while other voters who were once classified as “Reagan Democrats” are changing their party affiliation to Republican.

“The basic net-net is more people moving from Democratic registration to Republican registration,” she said.

“The bulk of that has been folks you might call Reagan Democrats — people who were registered as Democrats but are in communities where there’s been a pretty steady shift to identifying more with Republicans — slowly changing their registration to match their voting preference,” she explained.

“These are folks in the Rust Belt communities,” she added. “The bigger picture is the decline of union strength and the movement of economic dynamism elsewhere has fractured the connection between Democratic voting and old industrial areas.”

Democratic strategists in Pennsylvania and North Carolina acknowledge that their party’s voter registration advantage has eroded in those two key states since Biden won Pennsylvania and narrowly lost North Carolina in 2020.

They say the shifting registration numbers are catching up to voting behavior, as registered Democrats who voted for Trump or other Republicans have only recently come around to changing their party registration.

And they argue that many new voters registering as independent or unaffiliated with any party are likely to support Harris over Trump.

“What’s happening is that some registered Democrats are changing parties to reflect how they’ve been voting for years. A 2020 Trump voter who changes his registration from Democrat to Republican in 2024 doesn’t indicate much about how voting in Pennsylvania will change in 2024,” said J.J. Balaban, a Democratic strategist based in Pennsylvania.

In North Carolina, Democratic strategist Morgan Jackson said younger voters who are likely to vote for Harris are increasingly registering as unaffiliated. And he said one major reason is that both parties have a bad reputation.

“Yes, Democrats’ registration has dropped and Republicans’ has moved up marginally, but the truth is that people are just registering as unaffiliated. The unaffiliateds now make the largest segment of voters,” Jackson told The Hill. “I have to tell you I think it’s because both national party brands are in the crapper with voters.”

“Especially a lot of new, first-time voters. They just don’t have an allegiance to the party. But I will tell you that what we see is that unaffiliated voters, the large majority of them, are not unaffiliated. … Most of them align with one party or the other,” he said. “There’s a small segment of people in that sliver that truly are ping-pong voters, that are swing voters.”

The Hill/Decision Desk HQ gives Trump a 64 percent chance of winning North Carolina and finds him with a 1-point advantage over Harris in polling averages for the state.

Paleologos says the margins between the parties in voter registration have shifted in two other swing states, which are presidential and U.S. Senate battlegrounds: Arizona and Nevada.

Constantin Querard, an Arizona-based Republican strategist, said GOP officials and activists have made a concerted push to increase Republican Party registration in the state.

“The Republican Party gets credit for actually going out and doing the work on the ground that needs to be done,” he said.  

He said Republican voter registration nationwide has increased by 1.2 million people, while Democratic voter registration has dropped by 800,000 people since 2022.

“Nationally, you’re talking about a 2 million-vote swing toward Republicans in the last two years,” he said. “The Republican brand is doing better than the Democratic brand. I don’t think it’s surprising to see the sorts of gains we’ve made in Arizona.”

In Arizona, Republicans have doubled the voter registration advantage they had over Democrats in 2020, when Biden won the state.

“When you look at Arizona, which Biden won … Arizona had a net registration advantage for Republicans of 130,000, but that’s doubled. Now the Republican registration advantage in Arizona is 259,000,” Paleologos said.

He said that explains why the Suffolk University poll conducted in late September showed Trump leading Harris by 6 points in Arizona.

“I wasn’t shocked we had [a] Trump plus-6 state in Arizona,” he said. “When you look at all of the factors, it made sense to me.”

In Nevada, Paleologos said Democrats have seen their voter registration advantage fall away.

He said Democrats’ had a net registration advantage of nearly 79,000 in 2020. It has since fallen to a net advantage of 29,000 registered voters.

“It could be enough to keep it close, or it could go to Trump, just because they’ve lost 50,000 net registered Democrats,” he said.

Jon Ralston, CEO of The Nevada Independent and a leading political commentator in the state, said the Democratic voter advantage in Nevada was about 5 points in 2020 and it now stands at 1 point.

“It’s not because the Rs have gained, they have just lost many fewer voters as indie voters have exploded. Still, it’s a concern for Dems,” he wrote in an email to The Hill.

Ralston observed in a recent column that the “shifting” registration numbers in Clark County, Nevada’s most populous county, has made Democrats “apparently vulnerable.”

From Oct. 1-9, Republicans gained at least 1,118 more registrations than Democrats in the county.

That’s a departure from what happened over the first nine days of October in 2018, 2020 and 2022. In each of those previous years, Democrats gained more than 2,000 more Clark County registrations than Republicans.

Clark County has more than 2.3 million people, more than two-thirds of the entire state’s population. Biden carried the state by a margin of 33,500 votes in 2020.