What was uncle sam propaganda used for?

Uncle Sam propaganda was used to unify the United States of America and to promote loyalty to the government of the day. Uncle Sam's initials are actually the U S in the USA. It originated in the 1812 war and was used to encourage American citizens to enlist in the army during World War II. The meme Uncle Sam was based on a meat packer who supplied meat to the soldiers in the War of 1812. His name was Samuel Wilson. 

made it hard on soliders and civilians to get money food.