In this interview with Bill Kristol, Chris DeMuth, the former president of the American Enterprise Institute, describes why he shifted right. One factor was:

“stumbling into a friendship with a professor at Harvard named Edward C. Banfield. I first encountered Banfield in the form of a pamphlet published by the American Enterprise Institute, which one of my professors had assigned, I think as an example. They were trying to bow toward diversity of intellectual opinion. And he had written a piece on foreign aid. It challenged every doctrine, every precept, every pro-foreign aid argument, root and branch. And I remember being astounded by this publication.”

You can read the transcript and keyword search it for “Banfield” at https://conversationswithbillkristol.org/transcript/christopher-demuth-transcript/.