Reblog from Patheos.com.
Here is a selective excerpt:
There is no doubt in my mind that both Romney and Obama described America in such religious and exceptionalist terms because they are trying to win the election. As a nation we want to believe that we are special–a source of categorical good in the world. We want to believe that we are the greatest nation in the world, but more than that, that we are making the world a better place…
…My concerns about such glowing descriptions of America is that they assume things about our nation that may or may not be true. And such assumptions keep us from looking at the state of our union with sober judgement and consequently from seeing our weaknesses and failures. As Christians, we ought to hope that America would be a source of good in the world. But it is the height of hubris to assume that we are the greatest nation in the world. As Christians, we ought to be concerned primarily with God’s judgments over and against the judgments of others. And further, we should be very careful in presuming to speak for [God].
Hopping Hadrian's Wall 
Thank you — I have long felt this way, probably because I grew into young adulthood at the close of the Vietnam War, when so many of my friends’ lives were thrown away in that horrible event. My parents, however, members of “The Greatest Generation,” a generation of Americans that (I believe) literally DID save the world, feel I’m being unpatriotic when I say this. I try to tell them that times change, and if Vietnam had been “their war,” instead of WWII, they might feel differently. (Mostly I just avoid talking to them about this at all.)
Agree.
To someone who was born and raised and lives outside the USA, the whole idea of American exceptionalism has and always will be absurd. It is a rather narrow minded, and very self absorbed view, which I doubt anyone outside the US takes seriously. We kind of giggle at it actually. There has been great good come out of the United States of course, and of those things it should be proud, but seriously..the ONLY hope of the earth? Heaven help the rest of us if it is.