That's the exact message they are sending to the world, esp. their allies in the Middle-East. If they step out of line... BOOM !!!
Egypt has already seen changes in the leadership otherwise it too would have had the same fate as Libya. There is also trouble brewing in Iran. The signal is that the current regimes/governments need to understand that the US can destabilize any country at will.
The reason France was so eager was their long colonial history with Libya and ofcourse; oil.
Many people may have been right... the Crusades may have begun once again. For those of you who might say that Pakistan will do this or that, think again. We are already being pounded by drones. Our F-16s are American made alongwith many other equipment. If we do not currently have Friend-or-Foe transponder codes, it will be a lot more difficult defending against USAF.
The US may not send ground troops in this battlefield, but then it does not need to do so. Its air and missile strikes will be sufficient for the job.