Hoping to spur the creation of a transcontinental railroad, in 1853 Senator Douglas proposed a bill to create an organized territorial government in a portion of the Louisiana Purchase that was north of the 36°30′ parallel, and thus excluded slavery under the terms of the Missouri Compromise.
After pro-slavery Southern Senators blocked the passage of the proposal, Douglas and other Democratic leaders agreed to a bill that would repeal the Missouri Compromise and allow the inhabitants of the territories to determine the status of slavery.
In response, Free Soilers issued the Appeal of the Independent Democrats, a manifesto that attacked the bill as the work of the Slave Power.
Overcoming the opposition of Free Soilers, Northern Whigs, and many Democrats, the Kansas–Nebraska Act was passed into law in May 1854.
The act deeply angered many Northerners, including anti-slavery Democrats and conservative Whigs who were largely apathetic towards slavery but were upset by the repeal of a thirty-year-old compromise.
Pierce's forceful response to protests stemming from the capture of escaped slave Anthony Burns further alienated many Northerners.

Throughout 1854, Democrats, Whigs, and Free Soilers held state and local conventions, where they denounced the Kansas–Nebraska Act.
Many of the larger conventions agreed to nominate a fusion ticket of candidate opposed to the Kansas–Nebraska Act, and some adopted portions of the Free Soil platform from 1848 and 1852.
One of these groups met in Ripon, Wisconsin, and agreed to establish a new party known as the Republican Party in the event that the Kansas–Nebraska Act passed.
Though many Democrats and Whigs involved in the anti-Nebraska movement still clung to their partisan affiliation, others began to label themselves as Republicans.
Another political coalition appeared in the form of the nativist and anti-Catholic Know Nothing movement, which formed the American Party.
While the Republican Party almost exclusively appealed to Northerners, the Know Nothings gathered many adherents in both the North and South; some individuals joined both groups even while they remained part of the Whig Party or the Democratic Party.

Congressional Democrats suffered huge losses in the mid-term elections of 1854, as voters provided support to a wide array of new parties opposed to the Democratic Party.
Most victorious congressional candidates who were not affiliated with the Democratic Party had campaigned either independently of the Whig Party or in fusion with another party. "
Bleeding Kansas", a struggle between anti-slavery and pro-slavery settlers for control of Kansas Territory, escalated in 1855 and 1856, pushing many moderate Northerners to join the nascent Republican Party.
As cooperation between Northern and Southern Whigs appeared to be increasingly impossible, leaders from both sections continued to abandon the party.
In September 1855, Seward led his faction of Whigs into the Republican Party, effectively marking the end of the Whig Party as an independent and significant political force.
In May 1856, after denouncing the Slave Power in a speech on the Senate floor, Senator Sumner was attacked by Congressman Preston Brooks, outraging Northerners.
Meanwhile, the 1856 American National Convention nominated former President Fillmore for president, but many Northerners deserted the American Party after the party platform failed to denounce the Kansas–Nebraska Act.

The 1856 Republican National Convention convened in Philadelphia in June 1856.
A committee chaired by David Wilmot produced a platform that denounced slavery, the Kansas–Nebraska Act, and the Pierce administration.
Though Chase and Seward were the two most prominent members of the nascent party, the Republicans instead nominated John C. Frémont, the son-in-law of Thomas Hart Benton and a political neophyte.
The party campaigned on a new version of an old Free Soil slogan: "Free Speech, Free Press, Free Men, Free Labor, Free Territory, and Frémont".
With the collapse of the Whig Party, the 1856 presidential election became a three-sided co
Hoping to spur the creation of a transcontinental railroad, in 1853 Senator Douglas proposed a bill to create an organized territorial government in a portion of the Louisiana Purchase that was north of the 36°30′ parallel, and thus excluded slavery under the terms of the Missouri Compromise. After pro-slavery Southern Senators blocked the passage of the proposal, Douglas and other Democratic leaders agreed to a bill that would repeal the Missouri Compromise and allow the inhabitants of the territories to determine the status of slavery. In response, Free Soilers issued the Appeal of the Independent Democrats, a manifesto that attacked the bill as the work of the Slave Power. Overcoming the opposition of Free Soilers, Northern Whigs, and many Democrats, the Kansas–Nebraska Act was passed into law in May 1854. The act deeply angered many Northerners, including anti-slavery Democrats and conservative Whigs who were largely apathetic towards slavery but were upset by the repeal of a thirty-year-old compromise. Pierce's forceful response to protests stemming from the capture of escaped slave Anthony Burns further alienated many Northerners.
Throughout 1854, Democrats, Whigs, and Free Soilers held state and local conventions, where they denounced the Kansas–Nebraska Act. Many of the larger conventions agreed to nominate a fusion ticket of candidate opposed to the Kansas–Nebraska Act, and some adopted portions of the Free Soil platform from 1848 and 1852. One of these groups met in Ripon, Wisconsin, and agreed to establish a new party known as the Republican Party in the event that the Kansas–Nebraska Act passed. Though many Democrats and Whigs involved in the anti-Nebraska movement still clung to their partisan affiliation, others began to label themselves as Republicans. Another political coalition appeared in the form of the nativist and anti-Catholic Know Nothing movement, which formed the American Party. While the Republican Party almost exclusively appealed to Northerners, the Know Nothings gathered many adherents in both the North and South; some individuals joined both groups even while they remained part of the Whig Party or the Democratic Party.
Congressional Democrats suffered huge losses in the mid-term elections of 1854, as voters provided support to a wide array of new parties opposed to the Democratic Party. Most victorious congressional candidates who were not affiliated with the Democratic Party had campaigned either independently of the Whig Party or in fusion with another party. "Bleeding Kansas", a struggle between anti-slavery and pro-slavery settlers for control of Kansas Territory, escalated in 1855 and 1856, pushing many moderate Northerners to join the nascent Republican Party. As cooperation between Northern and Southern Whigs appeared to be increasingly impossible, leaders from both sections continued to abandon the party. In September 1855, Seward led his faction of Whigs into the Republican Party, effectively marking the end of the Whig Party as an independent and significant political force. In May 1856, after denouncing the Slave Power in a speech on the Senate floor, Senator Sumner was attacked by Congressman Preston Brooks, outraging Northerners. Meanwhile, the 1856 American National Convention nominated former President Fillmore for president, but many Northerners deserted the American Party after the party platform failed to denounce the Kansas–Nebraska Act.
The 1856 Republican National Convention convened in Philadelphia in June 1856. A committee chaired by David Wilmot produced a platform that denounced slavery, the Kansas–Nebraska Act, and the Pierce administration. Though Chase and Seward were the two most prominent members of the nascent party, the Republicans instead nominated John C. Frémont, the son-in-law of Thomas Hart Benton and a political neophyte. The party campaigned on a new version of an old Free Soil slogan: "Free Speech, Free Press, Free Men, Free Labor, Free Territory, and Frémont". With the collapse of the Whig Party, the 1856 presidential election became a three-sided co
Free Soil Party