The most significant stumbling block to implement Electronic Government in a sustainable fashion may be the development of software allowing parties to participate.
With the prospect of Electronic Government, demand on software developers may become very heavy. By its nature, custom-made software tends to the product of a few individuals enlightened in the specifics of a given application, which usually causes minor disasters (at least) as staffing changes. This is true for the design aspect of projects as well as the actual program code making up the application.
The only remedy is the establishment of far-reaching design and coding standards, allowing developers very little leeway in implementing actual projects. Creativity is expressed when making amendments to the design and coding standards, never in the actual implementations.