The nationwide release of the film Selma, which concentrates on Martin Luther King, Jr. and the 1965 Selma marches for the cause of African-American voting rights in the segregated South, has been received with much fanfare and enthusiastic accolades. It is likely to be short-listed for “Best Picture” from the voters in this year’s Academy Awards. Questions have been raised, however, about the film’s historical accuracy in its depiction of LBJ’s relationship to Dr. King, and his role in securing the Voting Rights Act, first by Joseph A. Califano Jr., chief advisor for domestic affairs to Johnson, and then by...