The new territories included California, which extended so far North and South of the Missouri line that both sides claimed it.
A deal had to be put together, and California was admitted to the Union as free soil, in exchange for a couple of new slave-states and a promise to enforce the Fugitive Slave Law more rigorously.
As the Abolitionist lobby was gaining more influence in Congress, this raised the temperature of the debate, especially after the publication of 'Uncle Tom's Cabin' soon afterwards.
The Mexican-War reignited the slavery question, as many of the acquired lands from Mexico became pro-slavery states territories. For example, Texas and New Mexico became pro-slavery while California and Utah didn't. Ultimately, this led to the American Civil War.
Abraham Lincoln and Stephen Douglas were the two participants in the great debate over slavery prior to the election of 1858.
the admission of California as a free state
One reason that slavery became a public debate was Uncle Tom's Cabin, this novel exposed many Northerners to slavery for the first time ever. Also the invention of the cotton gin greatly increased the need for slave labor, so their was a boom in slavery in the South.
Virginia legislature
What kind of territories to create in the new lands. Should the status be created by Congress or should Popular Soverignty be permitted. How many states should be created and how to draw their borders.
threatened to split national politics along the North-South lines.
All provoked increased debate over slavery
The southern lawmakers felt that slavery was a profitable business and did not want it to end and did not want to lose slave territory.
Expansion of slavery into acquired territories, such as Texas.
The Mexican-War reignited the slavery question, as many of the acquired lands from Mexico became pro-slavery states territories. For example, Texas and New Mexico became pro-slavery while California and Utah didn't. Ultimately, this led to the American Civil War.
Stephen A. Douglas
For the most part, the national debate on slavery was not whether to abolish it. Most Americans, especially in the North, did not want slavery to spread to the western frontiers.
Slavery
William Wilberforce
It was also a debate about the issue of slavery.
The main constitutional arguements during the debate over slavery were representation in Congress, importation of slaves, and the Bill of Rights.