President Coolidge and Secretary Hoover
President Calvin Coolidge, left, and Herbert Hoover stand together in 1928. From 1921 to 1928, Hoover served as secretary of commerce for Presidents Warren Harding and Coolidge. Secretary Hoover developed navigation, irrigation, and flood control projects. As chairman of the Colorado River Commission, he oversaw the interstate cooperation that led to the construction of the Hoover Dam.