The blue wave crashed down on Pennsylvania again, as voters from Philly to Delaware County turned left

The political forces that shaped last year’s midterm elections showed no signs of abating Tuesday, as voters turned on Republicans and establishment Democrats alike in races from Philadelphia and Scranton to the suburbs of Delaware and Chester Counties.

Outside Pennsylvania, voter unrest with President Donald Trump and the Republican Party he has taken over helped deliver victories for Democrats in Kentucky, where they narrowly took the governorship, and Virginia, where they seized complete control of the state government for the first time in more than a quarter-century.

Locally, Democrats will hold all five seats on the Delaware County Council, a Republican stronghold since the Civil War, and also assumed a majority on the legislative body in Chester County. In Bucks County, Democrats captured the Board of Commissioners for the first time since 1983.

And in Philadelphia, a third-party insurgent candidate weakened an already marginalized GOP by securing one of the at-large City Council seats reserved for minority parties — a seat Republicans have held for decades.

» READ MORE: The Republican ‘bloodletting’ continued in the Philadelphia suburbs. What does it mean for Trump in 2020?

» READ MORE: Philadelphia Republicans endured a ‘preposterous’ election season. What’s next?

“It’s a new day in Delaware County,” said Elaine Schaefer, one of three Democrats elected Tuesday in Delaware County. Democrats had never held a majority on the County Council in its history, let alone every seat.

The Democratic victories around the country point to surging interest by liberal voters heading into the 2020 presidential election. That could be especially significant in Pennsylvania, which Trump won in 2016 — along with its 20 Electoral College votes — partly due to a dip in Democratic enthusiasm in Philadelphia and Pittsburgh.

In Philadelphia, Kendra Brooks became the first candidate from outside the two major parties to win a City Council seat in the 100 years since it adopted a modern legislative structure. Running as a Working Families Party candidate, Brooks won one of the at-large Council seats that the city charter effectively reserves for candidates from outside the majority party. For the last 70 years, those two seats have been filled by Republicans.

“We broke the GOP," Brooks said at a victory party in North Philadelphia. "We beat the Democratic establishment. ... They said a black single mom from North Philly wasn’t the right person, but we have shown them that we are bigger than them.”

» READ MORE: What’s the Working Families Party, and how’s it different from regular Democrats?

» READ MORE: Democrats make history by winning control of Delco

The election didn’t just showcase Democrats defeating Republicans, it also had progressive insurgents beating machine Democrats.

In Scranton, independent Paige Cognetti, who declined to seek the Democratic nomination in a special mayoral contest because, she said, she didn’t trust the party, was elected mayor. Cognetti will be the city’s first female mayor — and the first mayor-elect to give birth (her first child is due in December). She ran on a “Paige Against the Machine” slogan — a riff on the band Rage Against the Machine.

In Philadelphia, Brooks and fellow Working Families candidate Nicolas O’Rourke had been criticized by Democrats for threatening their own at-large Council candidates, even though the voter registration math would seem to make it impossible for a Democrat to lose in the city. Democrats outnumber Republicans by 7-1 in Philly, and none of the Democratic slate went down in defeat.

Brooks had the backing of Liz Fiedler, a progressive state representative, District Attorney Larry Krasner, and City Councilwoman Helen Gym. Brooks also benefited from the help of the national Working Families Party and the endorsement of Democratic presidential candidate Elizabeth Warren.

Some Philadelphia voters said Tuesday they wanted a shift further left, amid a Democratic presidential primary in which the two top candidates, Warren and Bernie Sanders, are progressive icons — never mind recent polling that suggests such a shift left could open a narrow path for Trump to win reelection.

» READ MORE: Brooks captured a City Council seat in a historic win for the Working Families Party and Philly progressives

“I think the party has to be open to progressives with these types of values,” said Claire Adler, 26, of Northern Liberties. “In some ways our local leaders are, but in some ways they’re not."

Harvey Finkle, 85, said he voted for Brooks because "anything might be better than Republicans.” And Brooks and O’Rourke "might be better than Democrats,” Finkle said.

The Pennsylvania suburbs, which will be crucial in the 2020 general election, turned even bluer Tuesday, following big GOP congressional losses in the midterm elections.

In Delaware County, the results for Republicans were catastrophic. All three Republican Council candidates and all four Republicans running for Common Pleas Court judgeships lost. Republican District Attorney Katayoun M. Copeland was ousted by Democrat Jack Stollsteimer, whose campaign received the support of liberal billionaire George Soros.

None of the losing Delaware County GOP candidates spoke during their watch party at the Springfield Country Club. Republicans and their allies had stated in the days before the election that a victory by Stollsteimer would increase crime in the county, directly tying him to Krasner. In brief remarks, Delaware County GOP Chair Tom McGarrigle said local residents should be scared, particularly by Stollsteimer’s win.

» READ MORE: Democrats won across the Philly region as Republicans are fading even on friendly turf

“That should concern every one of you that has a home a family or a business in Delaware County," McGarrigle said. "Because, you know what? You shouldn’t feel safe anymore.”

Stacy Maillie felt safe voting for Democrats. A nurse and a registered Republican, she voted Democratic after a 12-hour shift in the emergency room.

“I’m not happy with our current state of the Republican Party," Maillie said after voting at Springfield Township High School. "I think it’s too divisive, and I think that the Democratic Party is more tolerant and inclusive. I just find that the current Republican Party has become more extreme.”

Staff writers Justine McDaniels, Chris Brennan, Vinny Vella, Allison Steele, and Sean Walsh contributed to this article.