The general thought is that computers will make for a more a more accurate voting process. At least with punch cards everyone knows what they look like and clear-cut rules about what is and what isn't a vote can be defined. With software only a handful of technical people know where errors are in the program. This article concerns itself primarily with voting results that are sent out prematurely and the ability for campaign groups to hack into these results for adjusting their campaign midstream. But the greater potential for harm would be if someone hacks into the results and changes them or if any of the developers involved in writing the code would place code in the program that adds or deletes votes. The more complex the code gets the greater the potential for unintentional bugs to enter they system and wreak havoc.

States that use computer voting would be best off if they printed out the results for each voter and have them review the ballot before placing it in a box the old fashioned way. This would allow for a double check in case of a close election and would probably eliminate a lot of the ambiguity that comes from a punch card.

CNN.com - Gaffe casts doubts on electronic voting - Sep. 15, 2003