Small Wars Journal has an excellent explanation of 4GW by retired Marine Corps Colonel Gary Anderson. You may be startled by his final conclusion.
Briefly and I’m no expert, 4GW is asymmetric warfare in which a much smaller adversary sometimes defeats a much more powerful one. Our wars and conflicts increasingly have a 4GW tone. 9/11 was a classic example of a 4GW attack, as was the recent attack on the Westgate Shopping Mall in Kenya. The intent, among other goals, is to disrupt and demoralize the enemy, both economically and psychologically.
I don’t usually quote this much. However, I find the subject fascinating. Maybe you will too. For more on 4GW check out Zenpundit and, of course, Small Wars Journal.
Paraphrasing
In Fourth Generation Warfare, conventional armies of nation-states are increasingly challenged by non-state actors who use a combination of lethal and non-lethal tactics that are increasingly difficult for conventional forces to counter, even with revolutionary technology.
4GW strengths
Perhaps the greatest strength of armed non-state actors is that centralized leadership is not the key to success of the movement. Most are begun by charismatic leaders, but they are not dependent on such leaders for survival. Some would say that Al Qaeda has become more dangerous than ever since the death of bin Laden and the Taliban would go on quite nicely without Mullah Omar. It is quite likely that many of the young bucks in such organizations probably welcome the drone strikes that kill senior leaders; that means upward mobility. This is why the all drone strategies, so beloved by Vice President Biden and his ilk, are not having the desired result.
A second strength of 4GW warriors is that they are not constrained by rule of law, but they are not above using it when it is to their advantage.
A final strength of Fourth Generation Warriors is that their tactical execution is almost totally decentralized.
4GW weaknesses
The lack of communications is probably the greatest weakness of 4GW organizations because American and other first world nations’ intercept capabilities render telecommunications and the internet very dangerous for operational or tactical use.
The United States and most Western societies have proven much more resilient to the psychological approaches that many in AL Qaeda expected, and NATO has fought on for twelve years in Afghanistan despite an attritional approach by the Taliban. To be sure, 4GW has changed the way we live in the United States.
This lack of strategic communications also means that the Fourth Generational Warriors lack an operational level of war.
Another of the most critical weaknesses of armed non-state actors against the security forces of nation-states is the lack of quality control.
A final vulnerability, and probably the most dangerous one for Fourth Generation warriors is that they find it hard to handle success.
Conclusions
The Fourth Generation jihadists believe they are at war, and they treat that war seriously; we wish them away by trivializing them as mere criminals at our own peril.
The greatest domestic threat of Fourth Generation Warfare to the United States is not in physical damage or human casualties, but that in protecting ourselves from internal and external threats that we evolve into a national security state unrecognizable to the vision of our founders. That would be real defeat.