If Pennsylvania stages a surprise next week, it’ll come out of suburban Philadelphia. The four so-called collar counties (Bucks, Chester, Delaware and Montgomery) were once moderate Republican bastions. In the past two decades, the suburbs have gone for Democratic presidential candidates. You can’t win without them. Bucks (pop. 626,854) is the bellwether: A mix of educated middle-class, rural and blue-collar communities, it votes both ways in local elections—and always for the presidential winner. …

Republicans in the collar counties had little reason for enthusiasm before the first debate. The morning after Denver, the party office in Bucks was overrun with people looking for Romney-Ryan lawn signs. The Romney message strategy echoes that of Sen. Toomey and other successful GOP candidates here two years ago: Talk about jobs and debt, appeal to bipartisanship, and avoid the subjects of abortion and religion as much as possible.

As it happens, Mr. Romney is the first Northeasterner to get the Republican nod since the Connecticut native Bush 41 in 1988. He looks and sounds like Republicans whom Pennsylvanians have voted for in the past. Texas swagger and Sarah Palin didn’t play well in Bucks. …

A visible difference from 2008 is the improvement in the Republican ground game. As in Ohio, the Romney campaign has been able to tap local evangelicals and tea-party activists and has built up a decent infrastructure with 24 offices and 60 staffers in the state.