In a critical state that Trump won by only 44,000 votes in 2016, Tuesday’s results demonstrate that maintaining that narrow advantage will be an enormous challenge for the president next year.

“The anti-Trump sentiment in the suburbs hasn’t dissipated at all,” said Ryan Costello, a former Republican congressman from Chester County. “Democrats have won counties they never, ever, ever won. The trend from red to blue has accelerated in the last few years, and there’s only one reason for that."

The risk for 2020, he said, is “there is not a way to win Pennsylvania, Wisconsin and Michigan without holding your deficits down in the suburbs.”

The election wasn’t all good news for Democrats. While liberal activists were toasting historic victories in populous southeastern Pennsylvania on Tuesday night, Republicans were simultaneously raising a glass for first-ever wins in the western part of the state.

The GOP took the majority in Washington County’s local government for the first time this century. It also scored a rare triumph on the Johnstown City Council and flipped county commissions in Greene, Armstrong and Westmoreland counties in the west — where Trump’s strength runs deep.

“This affirms that Trump will be formidable in 2020,” said Democratic Lt. Gov. John Fetterman, who was formerly mayor of a hardscrabble steel town in western Pennsylvania. “It’s wonderful that we have Delaware County for the first time since the Civil War, but Washington County just went red for the first time in over 100 years.”

A political realignment has been underway for years in Pennsylvania: The GOP has bled college-educated voters in the southeastern suburbs at the same time that working-class white people have abandoned Democrats in the west.

Despite losing the Philly suburbs in 2016, Trump became the first Republican presidential candidate to carry the state since 1988 by scoring big wins in rural areas and onetime Democratic strongholds in western Pennsylvania. Republicans and western Democrats believe that the 2019 election showed that Trump could pull that off again.

“It’s Trump country, Trump country, unbelievable Trump country,” said former state GOP leader Rob Gleason, explaining the Republican victories in the region.

“It continues to be a tale of two Pennsylvanias,” he added. “I think the president still has a very good shot of winning Pennsylvania because the supporters in the counties that voted for him in 2016 have pretty much dug in their heels.”