Campaign contributions, partisan politics, and environmental polarization in the US Congress

Prior literature has shown strong and increasing polarization on environmental voting in the US Congress, with Democrats tending to support pro-environmental ("green") legislation and Republicans opposing it. Employing a regression discontinuity design, we provide a causal estimate of the effect of partisanship on the importance of campaign contributions from brown industries received by US legislators. Electing a Republican rather than a Democrat for the House (Senate) leads to an increase of 96% (70%) in the importance of contributions from anti-environmental ("brown") groups. We also find that greater dependence on brown groups is associated with less pro-environmental voting for legislators from both parties and the greater the importance of brown contributions the more (less) likely that a legislator breaks the party line when its party favors (opposes) pro-environmental legislation. Finally, we provide an analytical narrative of the rise and pattern of environmental polarization consistent with our empirical findings. (JEL D72, Q58)