The promise to bring back jobs in 2016 turned Pennsylvania red for the first time in two decades.
Communities that once had booming coal and steel industries saw jobs evaporate in decades of decline.
As the world moved to automation and cheaper production moved overseas, communities in the rust belt felt left behind.
Then in 2016 along came the billionaire who said “I understand you, I value you, I will fight for you”.
Workers who felt forgotten by the political establishment turned their backs on their democratic routes to “Make America Great Again”.
Will blue collar workers vote Trump again?
In the rust belt towns of Johnstown and Somerset, the resounding verdict among residents suggests yes.
It was tough to find anyone here who didn’t vote for Donald Trump last time and won’t again this time.
Kevin Sieg, who worked in a steel mill for 11 years, told Sky News: “He’s here for the good of America. He’s here for people like me.
“Those jobs all went to other countries. Why? Because of the steel industry and everything going overseas because it was so much cheaper.
“Now businesses are coming back. Within 20 miles of Pittsburgh, there’s fracking going on everywhere. It’s creating tens of thousands of jobs.”
Hotel worker Patty Sanner says Donald Trump still wins her vote “because he said he’d fight for us little people”.
Patty’s late husband was a coal haulier and her nephew works in the steel mills in Pittsburgh.
She said: “He’s really worried if Biden gets in he might end up losing his job. The steel mills might start shutting down.
“Now we see coal trucks running again. But if Biden gets in we’re going to lose all that because he wants clean air. He doesn’t realise that this is our lives.”
Mechanic Jim Livingstone said: “I voted for him the first time and he didn’t let me down all the way through this”.
“He gets results. This country needed a businessman running it for a long time because they know how to get results.”
Why do blue collar workers matter?
Donald Trump won by a margin of fewer than 45,000 votes in Pennsylvania.
To keep this critical swing state he needs to hold these voters.
His rival Joe Biden is a Pennsylvania native from Scranton and is looking to claw back these working class supporters.
The Trump campaign sees an opportunity here given a large number of white non-college educated people who didn’t vote in 2016 – and that’s the biggest demographic in the president’s support base.
Have voters’ lives improved after four years of Donald Trump?
The Summit diner in Somerset was packed with people who reflected on their livelihoods now compared with four years ago.
Construction worker Wayne Sisley said: “My taxes have gone down and I like the security that he puts into the country.
“Everyone that I know that’s in construction is pretty much backing President Trump.”
Mr Sisley admits the only reason he doesn’t have a Trump sign outside his house is because he and his wife worry it could make them a target.
“Construction has gone up significantly since President Trump has been in office,” he says.
“With President Obama everyone was scared to spend money. With President Trump everyone was spending money, the economy was great, then this virus came.
“If it wasn’t for this virus it would be a slam dunk for President Trump.”
Insurance agent Blake Henry says President Trump has fulfilled his promises.
He said: “Up until the pandemic he’s done what he’s said he would do.
“The coal and the oil and gas business affects me because when those guys are working they’re buying new vehicles, they’re buying houses and insurance, so I’ve definitely seen the impact because the prior administration was anti-coal and we had guys laid off, not working, and that impacts them hard – but I can also see it on my bottom line.
“I think he’s done a tremendous job.”
Diner waitress Cindy says Mr Trump has brought jobs to the state.
“We are only open until 2pm because we can’t find enough people to work here,” she explains.
“As far as jobs go, there are way more jobs than there were before. If you drive through town all you see is hiring signs everywhere.”
Does the reality match the perception?
During the presidential debate Donald Trump claimed he had brought back 700,000 jobs to manufacturing during his administration.
The fact checkers quickly corrected that to around 450,000 jobs prior to the pandemic.
Donald Trump’s job manufacturing growth has also not been anything extraordinary – it’s grown at around the same rate as during the Obama administration.
Another important thing to fact check – Donald Trump repeatedly claims Joe Biden will end fracking in Pennsylvania.
There are around 20,000 to 50,000 jobs in, or supported by, the state’s fracking industry.
Despite Joe Biden’s plans for green energy he has only pledged to ban new fracking permits – and only on federal land.
Are there any signs Trump has lost ground here?
Joe Biden has pulled ahead in the polls in Pennsylvania and now leads Donald Trump by seven points, according to a Reuters/Ipsos opinion poll on Monday.
The Democrats do well in Pennsylvania’s metropolitan areas but in the rural communities you still feel you’re in true Trump heartland.
Even Democrats Ron and Almeda Miller, who live in the rust belt town of Somerset, are considering lending their vote to Donald Trump.
“I just don’t know what to do,” says Almeda.
“He brought coal back, which you know we didn’t have, but we just don’t know what we are going to do. This is really hard.”
One hesitation in their undecided Trump vote is the president’s attitude.
“I don’t really like his attitude, the way he talks,” says Ron, who’s retired from a job in manufacturing.
“In that debate they had, every time Biden starts to talk he started talking over him. To me that’s no way to be on television and having kids watching that.”
Trump’s rough talk may be a turn off for some voters – for others it’s the reason they love him.
“I hate to say it to a Brit, but I really do care about ‘America First’, retiree Nate Forsey tells me.
In Somerset, Pennsylvania, that certainly appears to be the overriding feeling.
Four years on, many here still feel Donald Trump speaks like them – and, crucially, for them.