In 1916, the NCLC and the National Consumers League successfully pressured the US Congress to pass the Keating–Owen Act, which was signed into law by president Woodrow Wilson. It was the first federal child labor law. However, the U.S. Supreme Court struck down the law two years later in Hammer v. Dagenhart (1918), declaring that the law violated the Commerce Clause by regulating intrastate commerce. In 1924, Congress attempted to pass a constitutional amendment that would authorize a national child labor law. This measure was blocked, and the bill was eventually dropped.