The document summarizes the tensions between immigrant and native groups in the United States during the 1840s-1850s. Nativist groups feared losing jobs and influence to the large numbers of Catholic immigrants arriving from Ireland and Germany. This led to the formation of the anti-immigrant Know-Nothing Party which aimed to restrict immigration and deport immigrants. Violence increased as nativist mobs attacked Catholic churches while immigrants fought back. Ultimately, immigration made American culture more diverse and helped fuel economic growth during the Industrial Revolution.