Other countries (such as Finland if I'm not mistaken) use electronic voting systems. I don't recall that there is an issue with those systems per se. The electronic voting system that was used in Ireland was heavily criticised during its design phase by the Irish Computing Society. They said that there was no proper design specification issued for the equipment in the first case. In addition, they called for a paper-based auditing system (which wasn't included?). I can't find the link for this at the moment but this was back in 2004. It is possible to have electronic voting - but the original decision and specification was rushed through.