"One of the real motives for the invasion of Iraq was to give the
world a demonstration of American power. It's a measure of how
badly things have gone that now we're told we can't leave because
that would be a demonstration of American weakness."

Paul Krugman:The Vietnam Analogy,
The New York Times 16.04.2004.

What would happen if now China would invade Taiwan and North
Korea would invade South Korea? What could United States to
do to support these client states - except launch nukes and let
them die along with tens of millions of other Asians (and few
million Americans that the Chinese nuclear missiles could kill -
more would die later because of the radiation)?

Basically United States army is in the Middle East. United States
has now no capability to operate in a global scale, if the operation
demands large numbers of foot soldiers and other troops.