I'd say the core factor is the one that is the most difficult to establish: just how many plans for such attacks there are, and how advanced and sophisticated (i.e. dangerous) they are. I veer on the side of they're far less prevalent than many think, and have been encouraged -- which is not to...
Broadly this, although we're some considerable distance from achieving good -- irrespective of what is done from this point -- merely trying to conceive what constitutes the least-worst option.
Pleasantly surprised by how the vote is going on this thread. Here's my twopenneth worth:
-- there is far more legitimacy to this than Iraq, given the UN authorisation (although it was a general, rather than a specific, statement) last week
-- IS/ISIS/Daesch are a mutation out of other...