Herbert Clark Hoover, the 31st President of the United States (1929–1933), was a mining engineer and author. As the United States Secretary of Commerce in the 1920s under Presidents Warren Harding and Calvin Coolidge, he promoted government intervention under the rubric "economic modernization". In the presidential election of 1928 Hoover easily won the Republican nomination. The nation was prosperous and optimistic, leading to a landslide for Hoover over the Democrat Al Smith, whom many voters distrusted on account of his Roman Catholicism. Hoover deeply believed in the Efficiency Movement (a major component of the Progressive Era), arguing that a technical solution existed for every social and economic problem. That position was challenged by the Great Depression, which began in 1929, the first year of his presidency. He tried to combat the Depression with volunteer efforts and government action, none of which produced economic recovery during his term. The consensus among historians is that Hoover's defeat in the 1932 election was caused primarily by failure to end the downward spiral into deep Depression, compounded by popular opposition to prohibition. Other electoral liabilities were Hoover's lack of charisma in relating to voters, and his poor skills in working with politicians.