A Democratic state senator who represents a Northeast Pennsylvania district that voted for Barack Obama in 2012 and Donald Trump in 2016 dropped his party registration last week and declared he would caucus with Republicans in Harrisburg.

The next day, a veteran Republican state representative who represents a suburban Philadelphia district that voted for Mitt Romney and then Hillary Clinton announced he wouldn’t seek reelection in 2020.

The developments underscored trends that are cleaving Pennsylvania, and much of the country, along partisan and geographic lines. Even as Democrats have taken control of the once GOP-friendly suburbs, they’re ceding power outside major metropolitan areas, especially in rural and white working-class communities.

Democrats had considered both chambers of the Republican-controlled Pennsylvania legislature to be prime targets for a takeover in 2020. Winning a majority in the state Senate now looks like more of a long shot, strategists in both parties said last week. Republicans are expected to have a 29-21 edge there by next fall.

But the retirement of Republican State Rep. Stephen Barrar in Delaware County gave Democrats more momentum in their bid to take control of the 203-member House. Democrats say they are targeting more than 40 districts and need a net gain of nine seats for a House majority.

While Democrats say they’ll fight for the seats still held by a dwindling number of Republican incumbents in Southeastern Pennsylvania, they may need to develop a message that can win beyond the suburbs. In 2018, all of the Democrats’ House gains came in the Southeast: The party flipped 14 seats there but lost three elsewhere.

In local elections this month, the party swept to power in the Philadelphia suburbs and the Lehigh Valley. But Republicans took control of the southwestern counties surrounding Pittsburgh, a region that’s been trending conservative for years, as well as Luzerne County in the Northeast.

“We’ve got to talk to voters that no one talks to,” said Jamie Perrapato, executive director of Turn PA Blue, a grassroots group working to elect Democrats in state and local races.

The stakes are already high in Pennsylvania, which is expected to be a hotly contested battleground in the presidential election. But the elections down the ballot will influence state politics for the next decade, as the results will help determine how congressional and legislative maps are drawn in decennial redistricting.

State Sen. John Yudichak of Luzerne County shocked Harrisburg observers and dealt Democrats a blow last week in announcing he would leave their party and caucus with the GOP. “Registering as an independent is the only way I can faithfully and fully serve the people of Northeastern Pennsylvania,” Yudichak said in a statement.

(Most Pennsylvania voters who identify as independent are formally registered as “no affiliation.”)

Yudichak, who isn’t up for reelection until 2022 and says he supports former Vice President Joe Biden for president, criticized “partisan purists.” Luzerne was one of three Pennsylvania counties that flipped from Obama to Trump in 2016. Pennsylvania Gov. Tom Wolf, a Democrat, won the county en route to reelection last year.

“Before he switched, I would have said both chambers are in play in 2020,” said Chris Nicholas, a veteran Republican consultant who worked for the party-switching U.S. Sen. Arlen Specter.

“Congratulations, Bernie Sanders and Elizabeth Warren,” Nicholas added, suggesting Yudichak may not have felt comfortable with the party’s drift to the left.

Sen. John Yudichak of Luzerne County speaks with members of the media at the Pennsylvania Capitol in Harrisburg, Pa., Tuesday, Nov. 19, 2019. The Democrat in Pennsylvania's state Senate from an area that shifted decisively to support Donald Trump in 2016's presidential election is switching his registration to become an independent and will caucus with the Republican majority. (AP Photo/Matt Rourke)
Matt Rourke / AP
Sen. John Yudichak of Luzerne County speaks with members of the media at the Pennsylvania Capitol in Harrisburg, Pa., Tuesday, Nov. 19, 2019. The Democrat in Pennsylvania's state Senate from an area that shifted decisively to support Donald Trump in 2016's presidential election is switching his registration to become an independent and will caucus with the Republican majority. (AP Photo/Matt Rourke)

State Sen. Vincent Hughes (D., Phila.), head of the Senate Democrats’ campaign committee, rejected the notion that the caucus has moved too far left. He pointed to the Senate’s vote last week to increase the minimum wage from $7.25 to $9.50 an hour over two years — a modest hike compared to a national push by liberals to raise the minimum wage to $15 an hour. The House has not acted on the measure.

“There’s no [Alexandria] Ocasio-Cortez sitting in our caucus,” Hughes said, referring to the self-described democratic socialist congresswoman from New York. “There’s no Squad sitting in our caucus.”

He said Yudachik’s decision had “a very rotten smell to it.”

Yudichak’s decision, as well as a likely GOP win in an upcoming special election to fill a vacancy, should give the party an eight-seat Senate majority heading into November 2020.

Lt. Gov. John Fetterman, a Democrat, casts the tie-breaking vote as the president of the Senate. So Democrats would need a net gain of four seats to take control of the chamber.

Their targets include Republican Sen. Tom Killion, who represents parts of Chester and Delaware Counties. Democrats are also eyeing Senate districts in Erie and Dauphin Counties.

“We’re just going to have to work a little bit harder, double down a lot more,” Hughes said.

Democrats see an easier path in the House, and donors may now act accordingly. Democrats say they are targeting more than 40 districts. They need a net gain of nine seats to win a majority.

Barrar’s district was seen as one of the Democrats’ tougher challenges in the Southeast, but his retirement means the parties will compete for an open seat. The Upper Chichester Republican, first elected in 1996, said last week he would not seek reelection, citing health issues and saying he wanted to spend more time with family.

Democrats see potentially low-hanging fruit in a handful of districts that Clinton carried in 2016, some of them by double digits. Beyond the Southeast, seats in Dauphin, Monroe, and Allegheny Counties are expected to be contested.

“We’ve been working hard all year to build the infrastructure and raise the money and recruit the candidates to be in the position to flip the house next year,” said Delaware County Rep. Leanne Krueger, who heads the House Democrats’ campaign committee.