Are there any civilians any more?
The sheer numbers of such people in the developing world, plus the lack of education and opportunity, and an abundance of ruthless tactical leaders who will happily employ even children as tools, suggests that the age of highly trained professional assassins, soldiers, or even "terrorists" may well be over. The new assassin or terrorist may be every frustrated individual with nothing to live for, every true believer, and in some places every grieving man. A grim future. But perhaps, in some ways, necessary:
Given that there is more and more information about the origins of commodity and other products available to purchasers, and the activities undertaken by corporations and governments about these and their violations of the ethical standards of those purchasers, there is also more and more pressure to end a series of practices, e.g. rainforest destruction, child labor, prison labor, labor movement suppression, human rights abuses, that have hitherto been assumed to be outside the realm of civilian concern.
If, however, asymmetric warfare targeting offending civilians or taxpayers becomes the standard means of furthering such causes, there may simply be no way to avoid such retaliations for real or imagined harms. There may well be one person on this planet with sufficient grievance to seek out and harm one other such person who is indirectly responsible for harms done to loved ones.
Various news reports on the way Palestinian suicide bombers are compensated indicate that such motivates predominate, and that taxpayers to the Israeli government are indeed deemed morally responsible for all actions of soldiers on the West Bank. This argument has, then, proven effective in at least one major sustained conflict. It may well motivate other distressed peoples to adopt asymmetric warfare to end occupations, economic "exploitation", and destruction of natural ecologies and societies.
Urban warfare in asymmetric warfare
Unlike the conventional wars - where one army fights another army in wide open battlefields - the asymmetric warfare tends to take place inside densly populized urban terrain. Therefore, urban warfare is a prominent part of the asymmetric warfare. Usually, the weaker party is persuading the war to take place inside of its own cities for serveral reasons:
1. A populated city is much harder to conquer than an open field.
2. The urbanized city is much easier to defend because it is full with tall buildings, narrow alleys and sewage tunnels. The building can provide excellent sniping posts while the alleys are ideal for planting booby traps.
3. If the attacking force is a Western army, adhering to international law and western moral values, it must restrain from using heavy fire power and indiscriminate bombing. Thus, the party barricading in a city won't have to face warplanes, heavy artillery and massive tank assult.
4. "Media War": a war on urban terrain is bound to cause some civilian casualties and extreme damage to civilian property. Photos of dead civilians and ruined street broadcast on TV make a strong impact in favor of the party barricading in the city and undermine the moral of the attackinf force.
5. Often, the barricading party is using the immunity that civilian gain under international law in order to prevent attacks on its combatants. It mainly does it by using "Human Shield" - a tactic which is declared a war crime. The use of the weaker party in Human Shield is mostly ignored by the world media and different human right organizations.
Sources
Robert Kaplan, "The Coming Anarchy", The Atlantic Monthly, 1994?
Barbara Tuchman, "The Proud Tower, Europe 1880-1914" re: anarchist assassins
UN reports on use of child soldiers as assassins
Sun Tzu 6