Long the holy grail for USAF (IIRC, the idea -- or desire -- dates back to the US Army Air Corps) the ability to defeat an enemy solely from the air has gotten closer and closer over time.
I don't think we are there yet tho...
http://www.nytimes.com/2011/05/25/world/africa/25nato.html?_r=1&hpw&gwh=4D8EEC48A828AED19476BC88883B0773
From strategic bombing in WWII (Berlin, Dresden, Tokyo) to Drone attacks, we still cannot quite close the gap (w/o nukes).