In response to the nomination of Cass, the Barnburners began to organize as a third party. At a convention held in June 1848, in Utica, New York, the Barnburners nominated Van Buren for president. Though reluctant to bolt from the Democratic Party, Van Buren accepted the nomination to show the power of the anti-slavery movement, help defeat Cass, and weaken the Hunkers. At a convention held in Buffalo, New York in August 1848, a group of anti-slavery Democrats, Whigs, and members of the abolitionist Liberty Party met in the first national convention of what became known as the Free Soil Party.