[228]
After taking office, Polk used George Bancroft as an intermediary to offer Van Buren the ambassadorship to London. Van Buren declined, partly because he was upset with Polk over the treatment the Van Buren delegates had received at the 1844 convention, and partly because he was content in his retirement.[229] Polk also consulted Van Buren in the formation of his cabinet, but offended Van Buren by offering to appoint a New Yorker only to the lesser post of Secretary of War, rather than as Secretary of State or Secretary of the Treasury.[230] Other patronage decisions also angered Van Buren and Wright, and they became permanently alienated from the Polk administration.[231]

Election of 1848[edit]
Daguerreotype of Van Buren by Mathew Brady, c. 1849–1850
Though he had previously helped maintain a balance between the Barnburners and Hunkers, the two factions of the New York Democratic Party, Van Buren moved closer to the Barnburners after the 1844 Democratic National Convention.[232] The split in the state party worsened during Polk's presidency, as his administration lavished patronage on the Hunkers.[233] In his retirement, Van Buren also grew increasingly opposed to slavery.