Whatever the result, this will be a historic day in American history. There will never have been more full kit clowns at U.S. desks and cubicles across the nation. This is the day we have dreamed of over the past 17 months of qualifying, living and dying as 38 players swaggered through 16 games.
Beneath the confident veneer of the red, white and (occasionally stonewashed) blue polyester we are wearing, most fans are braced, experiencing giddy mood swings between "God Bless America" to Götterdämmerung. We crave so badly for the U.S. to be a coming force -- the Bitcoins of world football -- so we can give a generation of our children heroes' names such as Mix, Jurgen and Kyle.
But while Klinsmann's team have dominated CONCACAF, we cannot escape the gnawing awareness that the Yanks play in the "Star Wars" bar of soccer regions. And perhaps worse, every signature win they've celebrated comes with an asterisk.
They were the first Americans to win on the road in Estadio Azteca, but the victory came against what was essentially a Mexican B squad. The same could be said about the first win against Italy. The fantastic comeback against Bosnia-Herzegovina was won after second-half substitutions turned the game into garbage time. Last summer's edifying 12-game win streak was Gold Cup assisted.
Simply put, the U.S. are about to face the triple salchow of Ghana, Portugal and Germany, and we have no way of knowing exactly how good the Klinsmann-era United States are: Dare we dream, or is this the Dream-On Team?
I have spent the past three months embedded with this squad. That is a period in which Landon Donovan was ditched and Klinsmann pivoted from his talk of a U.S. team that could play assertive, aggressive, dominating football to a more pragmatic vision of a young, athletic, durable, hard-running, counter-attacking collective built for Brazilian climes.
Michael Bradley is the symbol and talisman. The phrenologists' dream is a dire wolf in cleats. How far Klinsmann risks pushing him upfield without exposing the back line may be the most crucial tactical dilemma for the team throughout this World Cup. Bradley will surge wherever he is positioned, channeling Inigo Montoya in "The Princess Bride": "Hello, Ghana. My name is Michael Bradley. You killed my father. Prepare to die."
In attack, much will depend on the self-confidence of Jozy Altidore, who has suffered in front of goal all season with Sunderland like Chuck Knoblauch at the end of his Yankees career. Concerns exist all across the back line, which is largely young, untested and has not had time to jell. Cristiano Ronaldo will salivate like a starving standard poodle looking at that back four.
The U.S.'s showing in 2002 gives us strength. A similarly young team played well-organized, passionate football on an exhilarating, unforeseen run, surprising both Portugal and Mexico on the way to meet Germany in the quarterfinal. President George W. Bush called the team to remind them, "A lot of people that don't know anything about soccer, like me, are all excited and pulling for you."
This backhanded compliment may have propelled the team. They dominated the game yet fell 1-0, departing with heads held high having proved that the U.S. could compete at the highest level of world football.
Yet it is hard not to be haunted by the twin memories of 1998 and 2006, both of which may have eerie parallels to 2014. In 1998, coach Steve Sampson made wholesale lineup changes on the eve of the tournament -- including veteran leader John Harkes -- bringing in a number of inexperienced players, including dual-national David Regis who had not played a minute in qualifying. The team ended up dead last with no points, scoring just once, in garbage time, during a humiliating 2-1 loss to CIA watch-list favorite, Iran.
In 2006, expectations were high as the U.S. peaked at number four in FIFA's idiosyncratic rankings two months before kickoff. Drawn in a group of death against Czech Republic, Italy and Ghana, the team's tournament hopes were eviscerated within 35 minutes as the Czechs destroyed them. They limped out in the opening round.
At 6 p.m. ET, our agonizing will become moot. Klinsmann's team will take the field and the progress -- or lack of it -- that has been made since his hiring in July 2011 will become evident to all. The coach told me the key to success or failure lies in the players' confidence that they can win when they step on the turf. May they do so in the spirit of Bill Pullman in "Independence Day": "We will not go quietly into the night! We will not vanish without a fight! We're going to live on! We're going to survive!"
Roger Bennett is a columnist for ESPN FC and, with Michael Davies, is one of Grantland's "Men In Blazers." Follow him on Twitter @rogbennett.