The political party that ran Martin Van Buren for president in 1848 as an anti slavery candidate was the Free Soil Party.
Explanation:
At the 1848 presidential election, the Whig Party nominated Zachary Taylor by a large margin. Millard Fillmore was nominated as his running mate.
Among the Democrats, Lewis Cass was nominated with William Butler as vice-president.
An important part of the Democrats opposed Cass's nomination, which was seen as pro-slavery. This group of Democrats left the party convention and founded the Free Soil Party and nominated former president Martin Van Buren and Charles Francis Adams as its candidates.
