Argumentation exposes individuals to conflicting viewpoints and can help them make more informed decisions based on the pros and cons of a particular issue. While recent studies of argumentation in Natural Language Processing have mainly focused on understanding the effect of various factors of persuasion (i.e. the source, audience, and language style), the impact of exploiting the relationships among controversial topics when predicting argument persuasiveness remains under-explored. In this paper, we model the relatedness among controversial topics utilizing an embedding-based method based on individuals' stances on the topics. We then leverage these topic embedding features and incorporate topic semantics features extracted from the arguments along with the previously studied factors of persuasion. We show that incorporating both types of topic relatedness features explicitly leads to significant improvement in predicting persuasiveness and also helps enhance generalization to rare topics, in a few-shot setting.