The decline began with the Payne-Aldrich Tariff Act of 1909, which was mostly lobbied for by American publishers who did not wish to compete with German publishers. By some estimates, the new tariffs on postcards were an increase of 300 percent. Many distributors imported large quantities of German-produced cards before the tariffs took effect, causing a glut in the market. German publishers began moving production to the United States shortly after the Payne-Aldrich Tariff Act to keep selling to the American market. Ultimately, the tariffs contributed to the end of the "golden age" as publishing quality decreased (American technology lagged behind German), and as public interest in collecting waned. The National Postcard Association was formed to combat unfair practices, low prices, and an excessive amount of unsalable postcards. Effects of the tariffs were reinforced by the British naval blockade of German merchant ships at the outbreak of World War I in 1914. Postcard manufacturers called off their annual conventions that year, and many shifted to greeting card production. The war cut off the importation of fine German-produced cards as well as dyes used for ink—which were largely produced by the German Empire. Production of some postcards would continue during the war, to support propaganda efforts and troop morale.