Abolitionism entered national politics on November 13, when a convention at Warsaw, New York, unanimously nominated James G. Birney for President. The convention was an open rebellion by the politically activated wing of the movement against the ideological leadership of William Lloyd Garrison and marked the first appearance of what would later emerge as the Liberty party.

Garrison’s antislavery newspaper, the Liberator , had been the most influential organ of the antislavery movement since its inception in 1831, but its increasingly strident repudiation of all political activity alienated those who believed in constitutional change. Garrison’s fight to make the country recognize slavery as a sin relied upon moral persuasion rather than partisan politics. His opponents began to see him as a liability to the cause and met at Warsaw to form a national party committed to ending slavery through political reform. The new party was still nameless when it made the repentant former slaveowner Birney its representative, but it coalesced into the Liberty party in time to contest the 1840 election. The new party posed no real threat to the Democrats or Whigs that year, but many veterans of the 1839 convention would continue their struggle as leaders in the later Free Soil and Republican parties.