Concerns over the spread of abusive content in social media have led online platforms to explore large scale community-level forms of moderation. As an alternative to full bans, Reddit has implemented quarantines of subreddits, limiting access to controversial communities without explicit removal. Previous evaluations of the effectiveness of quarantines have focused on their impact on toxicity in affected communities. In this work, however, we focus on examining the impacts of quarantines of political subreddits on issues of political engagement in the broader Reddit community. We present a case study of two ideologically distinct political subreddits, r/The_Donald and r/ChapoTrapHouse, and examine the impact of quarantines on activity, visibility, and political discussion. We find that while quarantines had a homogenizing effect on participation in political subreddits, they had limited impact on the visibility of community-internal issues and political language, due to the entrenchment of subreddit norms.