In 1848, antislavery Democrats and Conscience Whigs (in contrast to Cotton Whigs) merged with the Liberty party to form the Free Soil Party. Unlike the Liberty Party, which was dedicated to slavery's abolition and equal rights for blacks, the Free Soil party narrowed its demands to the abolition of slavery in the District of Columbia and exclusion of slavery from the federal territories. The Free Soilers also wanted a homestead law to provide free land for western settlers, high tariffs to protect American industry, and federally-sponsored internal improvements.
The Free Soil Party nominated Martin Van Buren as its presidential candidate, even though Van Buren had supported the Gag Rule that had quashed consideration of abolitionist petitions while he was President. In the following letter, Gerrit Smith discusses Van Buren's nomination. In the election of 1848, Van Buren polled 291,000 votes, enough to split the Democratic vote and throw the election to the Whig candidate Zachary Taylor.
I hardly need say, that I am deeply interested in the present movement against the extension of slavery; and that I infinitely prefer the election of the candidates, who are identified with it, to the election of the Whig and Democratic candidates. Gen. [Zachary] Taylor and Gen. [Lewis] Cass are proslavery candidates. Mr. Van Buren and Mr. Adams are antislavery candidates. The former are the shameless tools of the slave-power. The latter bravely resist it.
It is true, that, among all the persons, whom there was the least reason to believe the Buffalo Convention [of the Free Soil Party] would nominate for President, Mr. Van Buren was my preference. He was my preference, because I believed he would obtain a much larger vote than any of the others; and, that his nomination would go much farther than that of any of the others toward breaking up the great political parties, which, along with the ecclesiastical parties, are the chief shelters and props of slavery.
But it is not true that I shall vote for Mr. Van Buren. I can vote for no man for President of the United States, who is not an abolitionist; for no man, who votes for slaveholders, or for those, who do; for no man, whose understanding and heart would not prompt him to use the office, to the utmost, for the abolition of slavery. And, let me here confess, that I am not of the number of those, who believe, that the Federal Government has no higher power over slavery than to abolish it in the District of Columbia, and to abolish the inter-State traffic in human beings. On the contrary, I claim that this Government has power, under the Constitution, to abolish every part of American slavery, whether without, or within, the States; and that it is superlatively guilty against God and man for refusing thus to use it. The still higher ground do I take, that no man is fit for President of the United States, who does not scout the idea of the possibility of property in man, and who does not insist, that slavery is as utterly incapable of legalization, as is murder itself. Why is it not? Is it not as bad as murder? Is not, indeed, murder itself one of the elements in that matchless compound of enormous crimes?...There should be no surprise, that, from the day this Nation came into being until the present day, no white man has, in any one of the Southern States, been put to death, under the laws, for the murder of a slave.…