Part IV focuses on the role of private interests in shaping political accountability. In Chapter 12, Eleanor Neff Powell, Devin Judge-Lord, and Justin Grimmer examine the relationship among financial contributions to congressional members, constituency interests regarding energy regulation, and congressional oversight of the bureaucracy. The authors analyze a novel dataset of over 6,000 communications between legislators and the Federal Energy Regulatory Commission (FERC) from 2000 to 2018. This analysis suggests that Republican legislators are more likely to write to FERC on behalf of energy companies while Democrats are more likely to write to FERC on behalf of individual constituents, who overwhelmingly oppose energy company interests. The energy sector increasingly funnels campaign contributions primarily to Republican candidates, with Democratic candidates receiving about a third as much as their Republican counterparts. Finally, consistent with the argument that private interests influence congressional oversight, the authors find a statistically significant positive association between energy sector contributions and pro-business communications by legislators.