I can start off, and maybe I'll turn to Mr. Davies.
I think you've hit on a very important point about the nature of terrorism itself and the terrorist threat. The whole objective of terrorists is to undertake their activities to achieve their objective. They constantly change. Every effort that a country or a coalition of countries undertakes is exactly what the terrorist entity themselves look for to change and adapt to. Their ultimate goal is to achieve whatever it is they're trying to achieve, and they'll use whatever means, barbaric or not, to achieve that. A suicide bomber is a great example of how barbaric it can be at times and how dedicated people are.
The strategic drivers ebb and flow through time, with how robust the group is, how well-financed it is, how well-armed it is, and where it is operating. Do they have safe havens to operate elsewhere? Frankly, the pressure that the international community may be putting on the group will also change its nature. Always anticipating that is the challenge back home for intelligence agencies and law enforcement agencies. Again, that speaks right to the “prevent” and “deny” pillars in the strategy.