The various local and State movements were merged in one great convention, which met at Buffalo on the 9th of August, with imposing demonstrations.
Many of those composing it had held high rank in the old parties.
Salmon P.Chase of Ohio was selected as president.

The convention represented a genuine anti-slavery sentiment, and amid excitement and enthusiasm Martin Van Buren was nominated for President, and Charles Francis Adams for Vice-President.

The Barnburners, the anti-slavery Whigs, and the old Abolitionists, co-operated with apparent harmony under the general name of the Free-soil party; and the impression with many when the convention adjourned was, that Mr.Van Buren would have a plurality over both Cass and Taylor in the State of New York.

The management of the popular canvass was intrusted to Democratic partisans of the Silas Wright school, and this fact had a significant and unexpected influence upon the minds of anti-slavery Whigs.
In the first flush of the excitement, the supporters of the regular Democratic nominee were not alarmed.

They argued, not illogically, that the Free-soil ticket would draw more largely from the Whigs than from the Democrats, and thus very probably injure Taylor more than Cass.