Why do politicians sometimes deliver passionate speeches and sometimes tedious monologues? Even
though the delivery is key to understanding political speech, we know little about when and why political
actors choose particular delivery styles. Focusing on legislative speech, we expect legislators to deliver more emphatic speeches when their vote is aligned with the preferences of their constituents. To test this proposition, we develop and apply an automated video analysis model to speech recordings from the US House of Representatives. We match the speech emphasis with district preferences on key bills using data from the Cooperative Congressional Election Study. We find that House members who rise in opposition to
a bill give more passionate speeches when public preferences are aligned with their vote. The results suggest that political actors are not only mindful of public opinion in what they say but also in how they say it.
