As dissatisfaction with the wars in Iraq and Afghanistan has grown, the policy of “stop-lossing,” or the involuntary extension of a service member’s duty commitment, has become a locus of controversy. Although the term has been standard fare in military contracts since the Vietnam War, when the replacement of soldiers whose contracts had expired disrupted unit cohesion, stop-lossing is now a symptom of the military’s lack of manpower during a pair of extended, troop-intensive counterinsurgencies.

http://www.armedforcesjournal.com/2008/05/3480872

"Troop intensive"? Approximately 1% of the US military is in Iraq and approximately 0.25% is in Afghanistan.

Obviously the definition of "troop intensive" has changed in the past 60 years.

You are exactly right. The reason that no more troops are engaged in these wars is a "political" reason. Our political leaders have made a decision to "privatize" these wars. We have some 140, or 150, or 160 thousands of our warriors in theatre while we have some 160 or so thousands of privatized militias (think, Blackwater, for example.) involved in these same countries.
Our soldiers, sailors, and Marines are being used to propogate corporate interests.
Not that we don't face real problems. We do. But, these problems are being addressed from the point of view of those who make profits from these problems and therefore the military is being used as but a pawn for their own interests.

While stop-loss might seem unfair and even illegal, one must remember that up until now, the U.S. military has not had a strong need to activate those "little know codicils" that have always existed, any more than there was a strong need to utilize the National Guard and the Reserves. However, these types of actions have always existed, at least on paper since Vietnam. I am military retired. Until I am over 60, I am subject to recall to active duty. In essence, I am being paid "not to come to work" as they say.

Unless the U.S. either disarms itself, or stops going to war for any reason overseas, or reactivates the draft, these types of actions are appropriate. After all, it is an All-Volunteer military and governments seldom live up to contractual arrangements if there is a perceived need. It makes sense, especially if folks “still have obligations” that allows the U.S. government to activate practices such as stop-loss.