In the 1920s, Walsh headed the Senate investigation into the Teapot Dome scandal that involved top officials of the administration of President Warren G. Harding. He was chairman of the Democratic National Convention in New York in 1924 and in Chicago in 1932. Walsh opposed child labor and supported women's suffrage and, unlike most other Catholics, Prohibition. On December 18, 1927 Senator Walsh introduced a plan to investigate the country's electric industry. The investigation done by the Federal Trade Commission would continue through 1935 and eventually result in four of the most important laws governing the electric industry in the 20th century including the breakup of most of the large holding companies that formed during the 1920s.