THE PRESIDENCY
Two weeks after his throat and abdomen surgery, Lyndon Johnson was an uncommonly active convalescent. When Mexican President Gustavo Díaz Ordaz invited him to fly down from the L.B.J. ranch to join in an inspection of the $78 million Amistad (Friendship) Dam, which the U.S. and Mexico are building on the Rio Grande, Johnson accepted in a twinkling. Meeting Díaz Ordaz in the middle of a bridge spanning the river, he exchanged abrazos with him, then helicoptered to the dam site. In a speech on the Mexican side, Johnson declared that the binational project, which will provide flood control and...