I came across a nice essay Three Centuries of American Declinism on Real clear Politics
while surfing the net at work. Sadly it was too long for me to finish
during business hours and had to wait until the evening, but I highly
recommend that you take the time to read the whole thing. Basically it
helps to put the doomsayers into perspective, and in particular digs up
some of the problems of the "Greatest Generation" left after they're
"mission accomplished" moment, which quickly grew into the many horrors
of the so called "Cold War".
The essay mentions a litany of failure's from the cold war from Red
Chine to the absolute disaster of the Korean War, barely touches on
Vietnam (probably because it's well embedded in the International
psyche although one wonders what anyone actually knows about it in this
day an age?). Touches on America's allies' desertions, (not entirely
blamelessly, can anyone say Suez crisis?) as well as the oil shock and
the USSR's technological lead in the space race. It all adds up to
grim(or joyful if you dream of American decline) and I think these
things are lost upon people who take our current troubles out of
perspective and idolize the past as a golden age of just war fought by
the book(or convention).
Obviously the article doesn't go much into our current troubles, or
even our current commitments. But then again the little isolationists
don't really go into how to go from riding the tiger to a happy world
where everyone listens to the wise UN. They assume it will happen
because it must or that it simply a matter of making a proclamation and
all will be right in the world. Sadly it's not so easy because there is
not magic wand which will undo the last 80 years and bring back our
splendid isolation. It is our fate to deal with a globalized world
turned upside down. America government has made more than it's share of
mistakes in the last three hundres years, however it's still hear and
many of it's contemporaries are not and I suppose that is one the
themes in the linked article.