His most important legislative achievements include the National Industrial Recovery Act in 1933 and the Wagner-Steagall Housing Act of 1937. After the Supreme Court ruled the National Industrial Recovery Act and the National Recovery Administration unconstitutional, Wagner helped pass the National Labor Relations Act (also known as the Wagner Act) in 1935, a similar but much more expansive bill. The National Labor Relations Act, perhaps Wagner's greatest achievement, was a seminal event in the history of organized labor in the United States. It created the National Labor Relations Board, which mediated disputes between unions and corporations, and greatly expanded the rights of workers by banning many "unfair labor practices" and guaranteeing all workers the right to form a union. He also introduced the Railway Pension Law and cosponsored the Wagner-O'Day Act, the predecessor to the Javits-Wagner-O'Day Act.