The Democrats’ shellacking of Republicans in the Philadelphia suburbs Tuesday raised doubts about Donald Trump’s reelection prospects in the key battleground of Pennsylvania, as voters in the populous region signaled continuing discomfort with the president.

Democrats’ historic takeover of county governments in Delaware, Chester, and Bucks Counties built on the party’s success there in federal, state, and local elections since Trump took office. The results underscored a political realignment that’s been underway for decades — but accelerated by Trump’s election — in which suburban areas long controlled by the GOP have moved to the left, thanks in part to demographic changes.

That trend was also evident Tuesday in Virginia, where Democrats wiped out Republicans in the suburbs and took control of the state legislature. At the same time, rural areas across the country have become more Republican.

“There continues to be bloodletting and further erosion of suburban voters from the GOP,” said former U.S. Rep. Charlie Dent (R., Pa.), a moderate who retired from his Lehigh Valley-based seat last year. “I just don’t know how Republicans will be able to offset the losses in suburban and exurban communities with increasing tallies from rural voters.”

"Suburban Philadelphia’s extremely disappointing,” said U.S. Sen. Pat Toomey, the lone Republican holding statewide office in Pennsylvania.

Democrats also dominated races in the Lehigh Valley, racking up county government wins, as well as in races for judge and district attorney in Northampton County. And in the suburbs of Pittsburgh, a Democrat defeated an incumbent Republican on the Allegheny County Council with 60% of the vote.

Delaware County Council candidate Monica Taylor high-fives a supporter during the Delaware County Democratic Committee's election watch party at the Inn at Swarthmore in Swarthmore Pa., on Tuesday, Nov. 5, 2019.
TIM TAI / Staff Photographer
Delaware County Council candidate Monica Taylor high-fives a supporter during the Delaware County Democratic Committee's election watch party at the Inn at Swarthmore in Swarthmore Pa., on Tuesday, Nov. 5, 2019.

The dominant theme Tuesday was how nationalized local elections have become, said Sarah Niebler, a political science professor at Dickinson College in Carlisle, Pa. In Cumberland County, which voted for Trump in 2016, borough councils elected Democrats in Carlisle, Mechanicsburg, and Camp Hill.

“The idea that local elections are immune from the national political climate is increasingly not true,” Niebler said. “Partisanship is permeating all the way down."

But even as Democrats celebrated their victories, they cautioned it would be premature to write off Trump in 2020, particularly given that his name wasn’t on the ballot this week.

“The trends look good," said Mike Mikus, a Pittsburgh-based Democratic consultant who worked on local races in Southwest Pennsylvania. “But I think in the end, we have to brace ourselves for a really tough race.”

In the lone statewide contest Tuesday, for two seats on Pennsylvania’s Superior Court, Democrats and Republicans appeared likely to each win a seat. The Republican, Megan King, had been endorsed by Trump. And Republicans continued to rack up wins in southwest Pennsylvania, a former Democratic stronghold.

Trump’s coalition in 2016 ran through working-class areas that had voted for President Barack Obama, including Erie County in the northwest and Luzerne County in the northeast. Traditionally, most Republicans have won statewide by performing well enough in the Philadelphia suburbs and routing Democrats in the middle of the state, the “T” region.

“The Philly suburbs obviously are a serious concern for Republicans and something that has to be addressed immediately,” said Charlie Gerow, a Harrisburg-based Republican strategist. Conversely, he said, voting trends in southwest Pennsylvania and the “T” can still help GOP candidates win statewide.

“Now the big question is, does Trump have his own magic? Is he the exception to the rule?” said Christopher Borick, a pollster at Muhlenberg College in Allentown. “His special recipe for success rarely helps other Republicans, and more often his liabilities hurt other Republicans. But in the end, next year’s race for the presidency is all about him.”

The question for Trump may come down to whether his margins elsewhere in the state can overcome increasingly large deficits of the suburbs. And Democrats were eager Wednesday to highlight the scale of their wins there.

“It’s one of the most competitive regions in the country, and some of the most powerful governments in the state, and all of them turned blue in one night,” said Tommy McDonald, a media consultant for the Delaware County Democrats and for Paige Cognetti, who won an insurgent progressive campaign for mayor of Scranton. “A population larger than the size of Philadelphia just went from being led by Republicans to being led by Democrats.”

And Republicans didn’t disagree.

“Some of the old-time Republicans are probably rolling in their graves," said Manny Stamatakis, an insurance executive and major Pennsylvania GOP fund-raiser. “The last time we lost the courthouse in all five Southeastern counties — I can’t even remember when that was.”

In Philadelphia, an active campaign by two Working Families Party candidates likely fueled increased turnout. That’s something to watch for in 2020, too. As the number of voters in Philadelphia has increased, energizing turnout even slightly can lead to thousands or even tens of thousands of additional Democratic votes.

It remains to be seen whether Republicans’ continuing gains in rural areas can overcome their growing deficits in the suburbs. Voter rolls in the Philadelphia suburbs have grown by 313,676 people since November 1998, a 22% increase that outpaces the rest of the state’s 16% growth.

Of almost 1.3 million voters the state has added, one out of three registered in Philadelphia or its four suburban counties. The number of registered Democrats in the region increased 75% between 1998 and 2018. Republican registrations fell 14% over that time period, even as the overall population grew.

Hillary Clinton carried each of the four collar counties in 2016 and still lost. But if Trump’s standing were to erode further in the suburbs, he would face an uphill fight in Pennsylvania.

In addition to Tuesday’s results, internal Democratic polling suggests Trump is deeply unpopular in the Philadelphia region. For example, a poll of 400 likely voters conducted for Democrats in August found that 39% of likely voters in Delaware County approved of Trump’s job performance, while 58% disapproved.

An October poll from Franklin and Marshall College found that 52% of registered voters in Pennsylvania would vote for any candidate who is not Trump, 29% firmly support Trump, and another quarter are still deciding.

But in a sign of how polarized opinions of Trump are, his approval rating in the state hasn’t moved significantly since Democrats began their impeachment inquiry, a process that next week will move into public hearings. And in Pennsylvania, his seemingly low 35% approval rating is similar to Obama’s rating in the state at the same point in his presidency.

Republicans say Democrats may help reverse the GOP’s fortunes in the suburbs by nominating a more liberal candidate like Sens. Elizabeth Warren or Bernie Sanders. A New York Times/Siena College Poll released this week found Trump with a 1 percentage point lead in a hypothetical matchup with Warren in Pennsylvania, while former Vice President Joe Biden led Trump by 3 points.

“In some ways the Democrats, certainly at the federal level, are helping us with really radical ideas that I think most Pennsylvanians don’t support," Toomey said. He won reelection in 2016 in large part by outperforming Trump in the Philadelphia suburbs, holding down his losses in some places, and winning Chester County, where Trump lost big.

"But the results yesterday weren’t good for us, so we’ve got a lot of work to do,” Toomey added.

Republicans remain bullish on at least one GOP incumbent who survived last year’s Democratic thumping in the midterm elections: U.S. Rep. Brian Fitzpatrick of Bucks County. The House Democrats’ campaign arm on Wednesday pointed to the party’s takeover of the county Board of Commissioners as evidence that Fitzpatrick is “vulnerable” and “the district is trending in Democrats’ favor.”

But the Democrats won by only narrow margins in Bucks, and Fitzpatrick won reelection last year in a district Clinton had carried in 2016. Fitzpatrick survived by running as an independent-minded lawmaker who wasn’t afraid to break with his party on big votes like repealing the Affordable Care Act.

“Brian Fitzpatrick will have a very different electorate to deal with next year,” Gerow said. “He has proven himself to be a street fighter. And a survivor.”

Staff writers Jonathan Lai and Jonathan Tamari contributed to this article.