Why is the U.S.A the only remaining superpower in the world?

Is it?

But it can't lick Iraq.

Is it ?

The USSR has fragmented, but it is sitting on a fortune
China is the next major economy - it might feed itself
(but smartly they are buying up anything available)

Russia is looking forward to blackmailing the Germans, having the
French sweet-talk them and the British do a covert deal.

The joke is that Russia (proper) and China spotted the weakneses

My understanding of the word superpower is that it describes a country
with the ability to greatly influence the world as a whole.  Of course
this is possible by anyone with a nuke these days, but in general
money is what makes the world go around.

The US GDP (Purchase Power Paridy in 2005) is $12.4 Trillion.
In contrast, the 2nd highest GDP is China with $8.2 Trillion (but
notice that China has more than 4 times the population of the US so
GDP per person is 1/6th that of the US)
Then Japan ranks 3rd at 3.9 Trillion.

The US is by far the most dominant country in the world markets in
both production and consumption.  Whether you like US policy or not,
it's obvious to everyone that the US has a lot of power and influence
over many events worldwide.

Over the next couple decades (assuming no major negative events in
China), China will likely become more and more of a superpower.  The
dynamics between US/China will be very interesting during this
transition time.