A Princeton University professor said on Monday that he had resigned from the board of the Heritage Foundation, saying the conservative think tank’s president had refused to take down a video in which he defended the right-wing commentator Tucker Carlson’s friendly interview with Nick Fuentes, an openly antisemitic white nationalist. Robert P. George, a professor of jurisprudence, is the first such board member to resign over the actions of the Heritage Foundation’s president, Kevin Roberts. Mr. George had served on the group’s board since 2019. “I could not remain without a full retraction of the video released by Kevin Roberts,...