The underlying cause of the Irish-American conflicts in the 20th century can primarily be traced back to the struggle for Irish independence from British rule. Irish-Americans sought to support the cause of their ancestral homeland, which was marked by a history of oppression, discrimination, and sectarian violence, particularly between nationalist Catholics and unionist Protestants. This conflict deepened in the 20th century, especially during events like the Easter Rising in 1916 and later the Troubles, leading to a division that extended into the Irish-American communities, where emotional and political allegiances influenced societal pressures and activism in the United States.