At 8:46 a.m. Eastern, a couple dozen Chicago firefighters stood on the tarmac of Chicago O'Hare International Airport, a few hundred yards from Mitt Romney's parked campaign plane, for a moment of silence observing the 11-year anniversary of the first plane that hit the World Trade Center.

Romney, the Republican presidential candidate, was en route in the back seat of a Chevy Suburban on some highway somewhere in the suburbs of Chicagoland. He was missing an impromptu photo opportunity.