Wearing of the green originated when Irish Americans fought to obtain political status in the United States. Up until the mid-nineteenth century, most Irish immigrants in America were members of the Protestant middle class. When the Great Potato Famine hit Ireland in 1845, close to a million poor, uneducated, Catholic Irish began to pour into America to escape starvation. Despised for their religious beliefs and funny accents by the American Protestant majority, the immigrants had trouble finding even menial jobs. When Irish Americans in the country 's cities took to the streets on St. Patrick's Day to celebrate their heritage, newspapers portrayed them in cartoons as drunk, violent monkeys.
However, the Irish soon began to realize that their great numbers endowed them with a political power that had yet to be exploited. They started to organize, and their voting block, known as the "green machine," became an important swing vote for political hopefuls. Suddenly, annual St. Patrick's Day parades became a show of strength for Irish Americans, as well as a must-attend event for a slew of political candidates. In 1948, President Truman attended New York City 's St. Patrick's Day parade, a proud moment for the many Irish whose ancestors had to fight stereotypes and racial prejudice to find acceptance in America.