It would be the damage done. I think it's the wrong question to ask, with all due respect. I think that basically what you want to look at is the damage being inflicted on a country through a cyber-attack, and how we actually decide that this is so crippling it's actually putting the life of your citizens and your critical infrastructure at risk. That's how it's going to be discussed.
How you respond to it is also an issue for discussion. It doesn't mean necessarily that you're going to respond to it through your own cyber-defence system. It could be something different.
To me, I guess, the whole answer is not so much the vector of the attacks, be that cyber, missile, or whatever; it's the effect they will have on a country.