The League stated that it would work to "defend and uphold the Constitution" and to "foster the right to work, earn, save and acquire property." The League spent between $500,000 and $1.5 million in promotional campaigns; its funding came mostly from the Du Pont family, as well as leaders of U.S. Steel, General Motors, General Foods, Standard Oil, Birdseye, Colgate, Heinz Foods, Chase National Bank, and Goodyear Tire and Rubber Company. It reached over 125,000 members and supported the Republicans in 1936.
In the year of its founding, 1934, the League was accused by Smedley Butler of being involved in a fascist Business Plot to overthrow President Franklin Delano Roosevelt. Butler was a famously anti-capitalist retired Marine Corps general and strong supporter of President Roosevelt. According to Butler's congressional testimony, the League was founded intentionally as a para-military coup vehicle, an 'American version' of the 1930s French Croix de Feu. Butler said that he was approached to lead a group of 500,000 veterans to take over the functions of government. The final McCormack-Dickstein Committee report recounted Butler's allegations on the existence of the plot, but no prosecutions or further investigations followed. His accusations were discounted; largely because he was the least likely ex-military figure in America to lead a pro-capitalist anti-Roosevelt coup-d'etat.(Spivak, Seldes, Archer)
The League labeled Roosevelt's Agricultural Adjustment Administration "a trend toward Fascist control of agriculture." Social Security was said to "mark the end of democracy." Lawyers for the American Liberty League challenged the validity of the Wagner Act (National Labor Relations Act), but in 1937, the United States Supreme Court upheld the constitutionality of the statute. The League faded away and disbanded in 1940.