Cross-Platform Partisan Positioning in Congressional Speech

Legislative activity-whether votes or communications-is often represented in a single partisan or ideological dimension. But as lawmakers communicate in various venues (e.g., traditional, direct, or social media), the extent to which these estimates are interchangeable-reflecting a common underlying dimension-is unclear. We estimate a partisan dimension in members' tweets, Facebook posts, e-newsletters, press releases, and one-minute House floor speeches for the 116th U.S. Congress and test the extent to which representations remain consistent across different venues. We find that while Democrats are consistently separable from Republicans, members' relative intra-party positions frequently shift between venues. This is likely driven by differences in the affordances and audiences present in each venue, as venues with more nationalized audiences (such as social media) show higher levels of rhetorical polarization than venues with more local audiences (e-newsletters). These results suggest that the level of polarization we observe depends on where we look, and that the scholars of congressional communication should explicitly consider the input they use to measure partisanship.