Does the US military have a clear purpose?

http://www.csmonitor.com/Commentary/Opinion/2011/0701/Does-the-US-military-have-a-clear-purpose

An important question to ask, at a time when we are mired in three conflicts, two of which have dragged on for over eight years and none of which have a clear end in sight. The US military budget is eight times the size of the next largest country and over the past decade that has been a major reason for the deficit explosion. And as the author says, what exactly are we defending ourselves against in Libya? At this point, what exactly are we defending ourselves against in Afghanistan, if Al-Qaeda can just move into other countries?

It's time to stop nation-building, as a presidential candidate by the name of George W. Bush ironically said in 2000. But few seem willing to say it.