Taking a quick look at the Barack Obama national security ad that Jon commented on earlier, it occurs to me that it is probably no coincidence that the first modern challenge the ad cites--before the obvious threats of "loose nukes" and "oil money funding terrorism"--is cyber-attacks. It's not hard to imagine why the Obama camp thought this issue would provide a useful contrast with McCain.
On the other hand, I suppose the McCain campaign could always respond that his would be a presidency uniquely invulnerable to the threat of cyber-attack.
--Christopher Orr