The Commonwealth of Massachusetts played a significant role in national events prior to and during the American Civil War. Massachusetts dominated the early antislavery movement during the 1830s, motivating activists across the nation. This, in turn, increased sectionalism in the North and South, one of the factors that led to the war. Politicians from Massachusetts, echoing the views of social activists, further increased national tensions. The state was dominated by the Republican Party and was also home to many Radical Republican leaders who promoted harsh treatment of slave owners and, later, the Confederate States of America.