Why is the US government doing all this?
1. To prevent people (esp. Americans & Europeans) from questioning the continuation & enlargement of the NATO.
2. To get the American public used to the idea & reality of sending troops abroad even in a context where it is impossible to claim a 'quick, painless, and decisive' victory.
3. To secure the Balkans as militarily strategic areas under the US/NATO control, which will become very useful when Russian people, fed up with capitalism (= unpaid wages, collapsing living standards, diminishing life expectations, general chaos, mob rule, etc.), will finally stage some kind of uprisings (whose political character it is impossible to predict from here).
4. To erase the memory of Yugoslavia (which represented an alternative model of Socialism) by claiming that the region is (and has been always) nothing but competing ethnic groups whose interests the US/NATO claims to ajudicate, thus assuming political & ideological control.
Yoshie