MORRISVILLE, Pa. — Voters in Philadelphia's suburbs have whipped up wave after wave of anti-Donald Trump sentiment since 2016, hurling perhaps their biggest rebuke yet to the Republican this month.

With turnout well above the state average, the four growing Pennsylvania counties hugging Philadelphia provided a decisive margin for former Vice President Joe Biden, lifting the Democrat to victory in the battleground state and to the presidency.

Those suburban voters in Bucks, Chester, Delaware and Montgomery counties overwhelmed Trump's strong performances in many Republican counties elsewhere in Pennsylvania — performances that were even stronger than the massive margins he picked up on his way to victory in the state four years ago.

Much of the credit in suburban Philadelphia goes to Democrats' turnout. But Biden's margins there were likely impossible without help from a critical bloc: Republicans.

One of those Republicans was Janice Reed.

"I don't think Joe Biden is gonna set the world on fire, but I think he's what we need for right now," Reed, 65, said in an interview Friday while taking a break from vacuuming her home in Morrisville, Bucks County, a Delaware River town a few miles northeast of Philadelphia. "He doesn't appear to be nuts."

Biden led Trump by 63,000 votes in Pennsylvania, or nearly 1 percentage point, according to a tally of unofficial results by The Associated Press, with some vote counting still going on Friday. The AP called Pennsylvania for Biden on Nov. 7 at 11:25 a.m. Eastern time.

With a total of 876,000 registered Democratic voters going into the election, the four heavily populated suburban counties on the Pennsylvania side of the Delaware River provided more than 900,000 votes for Biden, or more than one in four the Democrat captured in his native state.

Biden won a margin of nearly 300,000 votes over Trump in those four counties. That's 50% bigger, or more than 100,000 votes more than the margin by which Democrat Hillary Clinton beat Trump there in 2016.

Without those votes, Trump would have won Pennsylvania.

"For as much emotional volatility that folks had over the past four years, the vote was pretty much the same across the rest of the commonwealth," said Ryan Costello, a former two-term Republican congressman from Chester County. "Trump got a few more votes here, Biden got a few more votes there."

Nowhere was the anti-Trump surge more evident than in Chester County, home to about 157,000 registered Democrats. There, Biden racked up about 181,000 votes — 40,000 more than Clinton picked up in 2016.

Trump improved on his 2016 margins in 48 counties by a total of about 90,000 votes. Biden won Philadelphia itself, the Democratic Party's workhorse in the state, but Trump even scrounged up more votes in the city, shrinking his margin of loss compared to 2016.

That meant Democrats had to find more votes elsewhere.

For decades, to win Pennsylvania, candidates needed to win Philadelphia's suburbs, or at least be competitive there. Voters there are more diverse, better educated and earn more than the rest of Pennsylvania, and they typically vote in higher proportions.

Trump smashed that mold.

He suffered a nearly 190,000-vote loss there in 2016 but won Pennsylvania anyway, eking out a 44,292-vote victory — amounting to less than 1 percentage point — by supercharging turnout among white, working-class voters across Pennsylvania.

Since Trump became president, Republicans lost more than a dozen legislative seats, control of three county governments and two congressional seats in Pennsylvania's Philadelphia suburbs.

In 2020, the suburbs returned with verve.

"This year, Pennsylvania's political gravity caught up with him," said Christopher Borick, a political science professor and pollster at Muhlenberg College in Allentown. "You can't get crushed by those amounts and survive."

Tom McGarrigle, chairman of the Delaware County Republican Party, said he has worked Election Day polls for 25 years and has never seen turnout — particularly Democratic turnout — like he did on Nov. 3.

But he also knows that Republicans helped Biden, including Republicans who voted for Trump in 2016. Trump lost Republicans primarily because of his lacking response to the coronavirus, McGarrigle said.

"People were dissatisfied," McGarrigle said. "Especially with the spike, he wouldn't wear a mask and then he got it, and then with this spike coming back around."

For Reed, a retired schoolteacher and mother of four, that was certainly the case.

A registered Republican who voted for Trump in 2016, Reed said she didn't approve of how Trump handled the pandemic.

She planted a "Republicans Against Trump" sign in her yard, the first time she has ever had a political yard sign, and voted a straight Democratic ticket to send a message to Republicans.

She voted for Trump four years ago because she thought all politicians did was fight and create a mess.

"I thought maybe it could be some kind of change," Reed said. "But it was a horrible change."