UPPER DUBLIN, Pa.--Donald Trump's narrowing path to the presidency depends on winning Pennsylvania. One of his advisers was quoted just this week saying that he will be "cooked" if he cannot prevail in the Keystone State.

The GOP nominee is counting on Rust Belt voters in western Pennsylvania, who have traditionally voted Democratic but been battered by deindustrialization, to come out in droves for him. He needs enough to offset Hillary Clinton's huge advantages in the urban areas of Philadelphia and Pittsburgh.

But that's not enough. He also needs to turn in a respectable showing in the vote-rich suburban areas outside Philly.

Two days of interviews in the so-called "collar counties" around the City of Brotherly Love reveal profound problems for Trump in this area, even as he visited for a rally. I canvassed two dozen voters at three different sports bars - before, during and after the Eagles game last Sunday - in places where there should be pockets of Trump support. Most of the people watching football were white men, a good demographic for Trump. But they were also college educated and had white-collar jobs, not so good demographics for him.

The experience buttressed the findings of a recent Bloomberg poll that found Clinton carrying these suburban counties with a 28-point advantage over Trump. That's an 18-point improvement on Obama's winning margin against Mitt Romney in 2012, when the Republican did not meaningfully contest the state until the final days. The Democratic nominee is carrying almost every single group in this area.

It's hard to overstate the strategic importance of these four suburban counties (Bucks, Montgomery, Chester and Delaware), which together account for more than one-fifth of the electorate in the Keystone State. It has been 40 years since a presidential candidate carried Pennsylvania without winning the so-called critical "suburban collar."

At the bars, in fact, it proved surprisingly difficult to find just one fan of The Donald during a day-long odyssey. It was, however, easy to find split-ticket voters, people supporting Clinton and Republican Sen. Pat Toomey for reelection.

In a reflection of just how demographically polarized this election has become, I asked these folks where to find Trump supporters. For the first time, a group of boisterous Eagles fans at Ye Olde Ale House sunk into contemplative silence. "Uhhhh, I don't know," said a 20-something chemist. Another stopped guzzling his beer. "Want me to Google like, an even sketchier bar than this one?" he asked. Brian, an IT specialist, said Trump's rhetoric "goes back to [Joseph] Goebbels, to Hitler." He said he could not think of a single friend or even colleague at work who backs the GOP nominee.

A chorus of independent-minded voters who said they have supported Republicans in the past wondered why Trump keeps coming back. He campaigned last week in nearby Newton. A personal trainer wondered "why he wastes the gas" to fly here. An Uber driver said Trump's time would be better spent in Ohio: "It's almost like, what is he even doing here? Why is he not spending more time there?"

Some of this is bigger than Trump. The area's changing demographics have shifted the counties measurably to the left over the past 15 years. But statewide Republicans have continued to do well, and a couple voters volunteered that they would have happily voted for John Kasich had he won the GOP nod.

Pennsylvania tends to be a siren song for Republicans. Bush played very hard in 2004 but came up 2.5 points short to John Kerry.

One theme which kept coming up is that Trump could have done much better. Four or five months ago, if he had actually "pivoted" - as the campaign kept promising - he might have made inroads. There is still little love for Clinton. But his lack of seriousness and the disclosure of the 2005 video that showed Trump speaking lewdly about women might have baked the cake. "I will never get over Trump's comments in that video," said one gruff-voiced woman, who teaches at an elementary school and thinks of her two teenage nieces every time she hears the Republican nominee talking. "It makes me shudder," said the self-described moderate. She went on to express concerns about Clinton's "lack of transparency" and said she may end up casting her ballot for Gary Johnson.