(Reuters) - The last time Democrats controlled the government in Delaware County, a suburb of Philadelphia, the U.S. Civil War had just ended.

FILE PHOTO: Voters cast their ballots in state and local elections at Pillow Boro Hall in Pillow, Pennsylvania, U.S. November 5, 2019. REUTERS/Mark Makela

But on Tuesday, Democrats ended a century and a half of Republican dominance. In two other Philadelphia-area suburbs, they captured Chester County’s board of commissioners for the first time in history and seized control of Bucks County’s board of commissioners for the first time since the 1980s.

The Democratic gains in Pennsylvania, a state crucial to U.S. President Donald Trump’s election in 2016, suggest Republicans have yet to staunch the bleeding in the suburbs, where voters have increasingly revolted against Trump’s heated rhetoric.

The results should “scare” Republicans ahead of the November 2020 election, said Douglas Heye, a strategist who previously worked for the Republican National Committee.

“More and more data suggests we’re seeing a flight away from Republicans in suburban areas,” Heye said.

There were warning signs in other historically Republican strongholds as well.

In Kentucky, where Trump this week held a campaign rally to bolster Republican Governor Matt Bevin’s reelection bid, a Democratic challenger scored an upset win driven in part by a strong performance in suburbs of northern Kentucky outside Cincinnati, Ohio.

In Virginia, Democrats captured total control of state government for the first time in a generation, flipping both chambers of the legislature on the strength of wins in the rapidly growing and diversifying suburbs of northern Virginia and the capital of Richmond.

Many vulnerable Virginia Republicans sought to keep the campaign focused on local issues. Trump notably did not campaign in the state down the stretch, even as he sought to flex his political muscle in Kentucky and Mississippi.

The election results underscore the challenge Republicans in swing areas face when Trump seeks re-election in 2020, including U.S. senators Cory Gardner of Colorado, Susan Collins of Maine, Thom Tillis of North Carolina and Martha McSally of Arizona: embrace Trump and risk alienating suburban voters, especially women, or keep your distance and risk losing Trump diehards.

“That’s the question every Republican up for reelection is asking themselves: how do you overperform Trump in suburban areas without hurting yourself with the base voters you absolutely need?” said Alex Conant, a Republican strategist who worked on Senator Marco Rubio’s presidential campaign.

Collins dismissed reading too much into the local elections, noting Republicans did well in other Kentucky races, including wresting the attorney general office from Democrats.

“I think this was an example of a very unpopular incumbent governor,” she said in an interview in Washington on Wednesday.

LESSONS FOR DEMOCRATS

Democrats may have their own lessons from Tuesday’s elections. In Kentucky, Democratic Attorney General Andy Beshear emphasized so-called “kitchen table issues” such as healthcare and education instead of Trump during the campaign.

That playbook was successfully employed by dozens of Democratic congressional candidates in swing districts last year, when the party seized control of the U.S. House of Representatives.

In the 2020 presidential race, Democrats are grappling with whether a moderate such as former Vice President Joe Biden or a liberal such as U.S. Senator Elizabeth Warren would be best suited to defeat Trump.

“One of the reasons Democrats have overperformed in swing districts in the last two years is that they’ve nominated a lot of moderates,” Conant said, adding that Republicans would likely claw back some suburban losses if Warren were at the top of the Democratic ticket in 2020.

It remains difficult to determine how the House impeachment inquiry is affecting voter choices. Bevin, the Kentucky governor, sought to capitalize on Republican anger over the issue, using impeachment in his advertising and defending Trump. It was not enough to win.

Republicans noted that Bevin was deeply unpopular after battling schoolteachers and unions.

Bevin, who trails by just over 5,000 votes, refused to concede the race, citing reports of unspecified “irregularities.” On Wednesday he filed for a recanvass, which is a review of vote totals from each county to ensure the correct figures were transmitted to the state elections board.

Tuesday’s outcomes also did little to suggest that Democrats have arrested their own slide during the Trump era in rural areas and small towns, according to Kyle Kondik, an elections analyst at the University of Virginia. Republicans made gains in local races in western Pennsylvania and in southern New Jersey.

“There are countervailing trends that may cancel each other out,” Kondik said. “I think the suburban problems for Republicans are very real, but I think the small city and rural problems for Democrats are also real.”