The following excerpts are from a 2020 article from the Proceedings of the National Academy of Sciences (PNAS). It is a report examining the influence of campaign contributions from oil and gas companies on the votes of legislators.

---

Abstract

Do campaign contributions from oil and gas companies influence legislators to vote against the environment, or do these companies invest in legislators that have a proven antienvironmental voting record? Using 28 y of campaign contribution data, we find that evidence consistently supports the investment hypothesis: The more a given member of Congress votes against environmental policies, the more contributions they receive from oil and gas companies supporting their reelection.

• “These findings provide strong and consistent support for the investment hypothesis and weak and inconsistent support for the influence hypothesis. That is, instead of attempting to sway undecided or opposing legislators’ votes, oil and gas companies seem to provide financial rewards to members of Congress after they have voted against legislation to protect the environment.”
• “Although results from this analysis indicate that money is used by oil and gas companies to systemically support anti-environmental politicians, these insights likely generalize to other areas of monied interests, such as those in the technological, financial, and pharmaceutical industries. The current findings provide an important step toward better understanding the role of campaign contributions in voting on environmental issues.”  
• “These findings provide strong and consistent support for the investment hypothesis and weak and inconsistent support for the influence hypothesis. That is, instead of attempting to sway undecided or opposing legislators’ votes, oil and gas companies seem to provide financial rewards to members of Congress after they have voted against legislation to protect the environment.”  
• “Although results from this analysis indicate that money is used by oil and gas companies to systemically support antienvironmental politicians, these insights likely generalize to other areas of monied interests, such as those in the technological, financial, and pharmaceutical industries. The current findings provide an important step toward better understanding the role of campaign contributions in voting on environmental issues.”