The San Bernadino shooters were a devout Muslim couple of Pakistani origin, they were wearing tactical armor and had sophisticated assault weapons, and were wearing GoPro cameras to capture footage of their killing for later dissemination. It's pretty clear this was a terrorist attack. In my opinion, they were probably seeking to mount a bigger attack on some juicier high profile target elsewhere, but wanted to settle scores with the husband's workplace first, before going out in a "blaze of glory" somewhere else. The police probably fortunately intercepted them before they made it elsewhere. (That's just my speculation)
As previously noted, ISIS has announced plans to expand its war to other countries like India. Given the widespread perception that India is a soft target, it's pretty clear that we need to expect another attack. I'm now wondering exactly where another attack will happen - probably a major soft target where they can get a huge amount of publicity. India needs to set up a military reserve or civil guard reserve, which can be mobilized at moment's notice. I think the next major attack is not far off, and it will probably be through some ISIS affiliate. Perhaps ISIS will try to reach out and join hands with LeT - no way to tell exactly, although ISIS does have some direct sympathizers among Indian Muslims.
And just like the previous 26-11 attacks, the Left-wing media and the "intellectuals" will quickly pounce upon such an attack to blame Modi. They'll be claiming that Modi isn't strong enough to stop terrorism, and they'll also claim that "divisive Hindutva politics" has only turned more Muslims into terrorists.
Meaqnwhile, let's see what happens to Trump's poll ratings.