In 2006 we are witnessing the finite limits of "projection of power" via military means. No matter how asymmetrical, any projection of power always reaches a point where it dissipates and is no longer effective.
Some goals simply cannot be achieved by military means, such as creating a democratic USA friendly utopia in Iraq by ... bombing the hell out of the place. Or creating a democratic, Israel-friendly utopia in southern Lebanon by ... bombing the hell out of the place.
The US adventure in Iraq and now the Israeli adventure in southern Lebanon are pointing to just how hard and stubborn the limits of military power can be in the 21st century. Military force, when actually used, is proving to be incredibly ineffective at achieving the goals for which it was employed. The robust international arms trade is erasing the asymmetry which used to allow Power A to completely overwhelm Power B, especially when Power A is being forced to engage Power B on Power B's home turf.
In the 1960s it cost millions of dollars to have a tiny fraction of the computing power of the computer on which I am now writing this. The same trend has occurred in weapons and will continue. While US or Israeli weapons (for example) may be this year's state of the art, and Hezbollah's weapons were the state of the art 5 years ago, the difference between the two is shrinking rapidly. This means that even poor countries or non-countries now have access to weapons that are extremely formidable and quite cheap. If this technological curve continues to flatten, which it appears will happen, the deciding factor in military actions will shift from superior technology to superior strategy. And because a defender does not have to worry about calls to "bring the troops home," it will always have an advantage over an aggressor from far away who is forced to "do the job quick, don't lose any soldiers, and don't kill any civilians."
These factors played an important role in Lexington, Massachusetts on April 19, 1775.