Who leads and who follows in Congress? We analyze the Twitter accounts of U.S. House of Representative members to develop a new understanding of House leadership power. Formal theoretic work on congressional leadership hypothesizes that party members shift their policy stances as they balance coordination and information problems. The theoretical work predicts that when coordination problems are pressing, legislative members follow the policy positions of party leaders. When their party’s information problem is more acute, party members instead give their leaders direction for the party’s agenda. Our empirical study uses the Joint Sentiment Topic model and tests these implications of this theoretical model using our Twitter data. Our analyses reveal that leader-follower relationships are complex. Party leaders possess the power to substantially affect the propensity of rank-and-file members to discuss topics, especially when the coordination problem dominates; however, when rank-and-file members influence discussion of a topic, their effect on leadership’s propensity to discuss it is far larger. These effects are particularly pronounced even when coordination problems are pressing. However, when the information problem is more acute, leadership influence decreases, consistent with theory. We show these results are robust to the the underlying dynamics of contemporary political discussion and context.