Final answer:
The Free-Soil ideology was central to the platform of the Free-Soil Party, formed to oppose the extension of slavery into new territories and protect the interests of free labor.
Step-by-step explanation:
The free-soil ideology became the heart of the Free-Soil Party platform. This party was founded by a coalition of anti-slavery factions, including disaffected Democrats known as the Barnburners, antislavery Whigs, and members of the Liberty Party.
The Free-Soil Party emerged in response to widespread concerns that southern slaveholders were using their wealth and power to control national politics, with the goal of protecting and extending the institution of slavery into the new territories.
The party's core message, encapsulated in the slogan "Free Soil, Free Speech, Free Labor, and Free Men," was to oppose the expansion of slavery and protect the interests of free white laborers from competing with enslaved workers.
The Free-Soil Party's emergence was a significant development in the political landscape leading up to the Civil War. It signaled the growing sectional divide and highlighted the central role played by the issue of slavery's expansion in American politics.
Although the party's impact in elections was limited relative to larger parties, its ideas and policies around the non-expansion of slavery were foundational in the creation and platform of the Republican Party, which ultimately rose to national prominence with the election of Abraham Lincoln in 1860.