Could a cyberterrorist unleash devastation on Interactive Democracy. Well, where there's a will there's a way!
One defence against an attack on the ID infrastructure is to build a discrete local cell structure so that the entire national ID system can't be attacked through a single gateway. An effective assault may damage one cell but the rest of the system would be unaffected.
My preferred design would allow voters to monitor their voting account history in the same way that we can monitor our online bank balance. Voting is analogous to spending money and the ID system would be as secure as the online banks which now have many years experience of secure operation. Corruption of an ID ballot could be reported by any user monitoring their "vote account" and reports of a distorted ballot would simply lead to it being recast at a later date when the IT defences have been repaired. In this way Interactive Democracy appears to be an illusive and resilient target for terrorists when compared to the banks, airlines or the Ministry of Defence IT systems, where attack could have immediate and catastrophic consequences.