Religious Conflict and Discrimination
Ill will toward Irish immigrants because of their poor living conditions, and their willingness to work for low wages was often exacerbated by religious conflict. Centuries of tension between Protestants and Catholics found their way into United States cities and verbal attacks often led to mob violence. For example, Protestants burned down St. Mary’s Catholic Church in New York City in 1831, while in 1844, riots in Philadelphia left thirteen dead.
Anti-immigrant and anti-Catholic sentiments in the 1840s produced groups such as the nativist American Party, which fought foreign influences and promoted "traditional American ideals." American Party members earned the nickname, "Know-Nothings," because their standard reply to questions about their procedures and activities was, "I know nothing about it."
In the Questions for Admittance to the American Party (1854), inductees committed to "…elect to all offices of Honor, Profit, or Trust, no one but native born citizens of America, of this Country to the exclusion of all Foreigners, and to all Roman Catholics, whether they be of native or Foreign Birth, regardless of all party predilections whatever." This commitment helped elect American Party governors in Massachusetts and Delaware and placed Millard Fillmore on a presidential ticket in 1856.