With a rusting steel mill in its center, this Pennsylvania city would seem fertile ground for Donald Trump's campaign and its vision of a declining America that only he can fix.

Yet Trump, who will be seeking voters' backing as the Republican nominee for the White House in the state's primary on Tuesday, may face a stiffer challenge than the demise of the local steel industry might suggest.

In the two decades since the blast furnaces of Bethlehem Steel went silent, the local economy did not follow the once-mighty company into decline. It bounced back.