Mr. Udall, WFB begins by telling us, is running for President, and "a number of Democrats ... see in him someone who could bridge the gap between, say, the McGovern wing of the party and the Muskie-Humphrey wing." (Historical piquancy: the others whom WFB mentions as serious candidates for 1976 are Henry Jackson, George Wallace, and Lloyd Bentsen.) But the substance of the conversation is on Mr. Udall's principal preoccupations: energy and the environment.