shadow warfare?

Yes, covert, non-conventional warfare. Sending small, specially trained groups to accomplish specific strategic goals, such as assassinations, kidnappings, interrupting supply lines, gathering information covertly, etc. "Shadow" being a metaphor for "covert," "hidden," "unseen," etc.

FBM said it pretty well. The only thing I would add is to ask why "shadow warfare" is "the only way to combat the new terrorist enemies". Note that one can use light infantry tactics and commando teams as part of a publicly acknowledged strategy. On the other hand, the covert element is necessary whenever a government doesn't want to be associated with or accountable for its actions. That might be the case when those actions violate American or international law, or the public ethos, or involve the violation of the sovereignty of foreign nations which are at least nominally our ally (e.g. Pakistan).

Incidentally, this thread had no forum distribution list. I took the liberty of adding tags for terrorism and war.

ESL is the only tag needed.

Incidentally, in the small screen, low resolution of my cellphone, it appears that Penny Chan is wearing a square of American cheese as a hat. Presumably that isn't the case (though you never know on the Internet), in which case, what is it and what is the cultural background for this item of apparel? On the other hand, if it is indeed a square of American cheese, how old is it? Do you wear a fresh slice each day, or reuse the same one? If the latter, does a specially sanctified storage unit exist for this item of ritual headgear, or do you just put it in the bedside drawer at night?

Thanks! It helps a lot!