The Russians have never been known for their finesse in dealing with terrorist attacks.
A few predictions...
1. The U.S is not and will not be prepared to deal with a Kenyan mall situation until after it happens, when there will be much hand-wringing, second-guessing and gnashing of teeth, mostly to no avail other than to wake up the populace, if only temporarily.
2. It likely won't happen in a state with a heavily armed population, but will go down in a gun-free zone to ensure maximum casualties.
3. A lot of politicians will lose their jobs.
4. A witch hunt and house cleaning will occur within the intel community.
5. We will bomb the living chit out of somebody, somewhere, until we're once again distracted by the peddled pablum of popular culture.
6. We won't be able to stay distracted, however, because we are in a mostly unrecognized (by the public) new kind of long-term struggle, and the next big attack will likely just be the beginning.
