In two months on the road covering the 2016 presidential primaries, I've seen the U.S. going through something of an identity crisis, after decades of dominance. The candidates are talking about what the voters are thinking about: What does it mean for America to be great? 

To a traveler, America's greatness is revealed in simple, visual ways. Everywhere, even in sparse rural areas, there's a healthy bustle of activity. Americans get up early, and they find it hard to keep still. At a Florida intersection, I watched a man expertly juggle a mattress-store sign to attract customers. He might hold the sign for minimum wage, but that's not why he juggles it.

The whole country is never in repose; an energy runs through it that you won't find anywhere else, and a sense of constant, habitual competition is ever-present. This is the biggest economy in the world, and it feels like it. It feels like a great nation.

To the presidential candidates, however, the issue of greatness is debatable.

David Fuller's view

America’s most attractive and inspirational quality of the 20^th Century, in my opinion, was that in this nation of immigrants people believed that they had the freedom and opportunity to achieve their realistic ambitions.

I believe that was an important key to America’s greatness.