A significant number of failures in e-voting systems have arisen because of poorly specified requirements, combined with an ad-hoc approach to engineering multiple variations of similar machines. We demonstrate that e-voting is a suitable domain for leveraging state-of-the-art in software product line (SPL) engineering techniques and tools. We propose, based on examples of typical requirements, that a feature-oriented approach to e-voting domain analysis is a good foundation upon which to carry out commonality and variablity analysis. Simple analysis of our core and optional features (and their variants) leads us to believe that feature interactions are a major problem in voting systems. We conclude that a formal software product line would help to manage the composition of features in such a way as to eliminate interactions in the requirements models, before particular e-voting systems are instantiated.