A few days before Christmas in 1959, Beale executed a will that essentially disinherited his youngest son, Thomas, who was ten years old at the time.
The dominant interpretation for the previous two decades was that of the Dunning School, which held that unscrupulous Northern adventurers, known as Carpetbaggers, manipulated the new black vote in the South to take control of state governments for their own advantage in terms of speculation, and corruption.
In his chapter, "Claptrap and Issues", Beale argued, "Constitutional discussions of the rights of the negro, the status of Southern states, the legal position of ex-rebels, and the powers of Congress and the president determined nothing.
[6][7] The Beard–Beale interpretation of the monolithic Northern industrialists was challenged in the 1950s in the works of several historians, including Robert P. Sharkey, Irwin Unger, and Stanley Coben, who argued that there was no unified economic policy on the part of the dominant Republican Party and no conspiracy to use Reconstruction to impose a unified economic policy on the nation.
Beale turned his attention to foreign-policy during the 1940s and published his major study of Theodore Roosevelt's foreign policy (the Shaw Lectures on Diplomatic History delivered at the Johns Hopkins University).
Beale, like Beard, felt both world wars were mistakes for the United States, and strongly disagreed with the interventionism and imperialism of Theodore Roosevelt.
However, in writing the 600 page monograph he changed his mind, deciding that Roosevelt had a remarkably deep comprehension of world affairs, and practiced very careful, very successful diplomacy.
He edited the diaries of Edward Bates (Attorney General) and Gideon Welles (Secretary of the Navy), who were members of Abraham Lincoln's cabinet.
[10] In 1950 Beale spoke out against the call by Conyers Read, President of the American Historical Association, for historians to be enlisted in the ideological struggle against totalitarianism.