1. The Wilmot Proviso is a proposed law by United States politician David Wilmot to ban slavery in western territories gained from Mexico in Mexican-American War.
2. The main issues that led to Henry Clay's proposed compromise were a. California applying for its statehood, b. fugitive slave law was created, and c. northerners wanted the slave trade to be banned in Washington DC.
3. The status of new western territories would be decided by popular sovereignty in which the citizens would be the one to decide (by means of voting) whether their territory would permit or ban slavery.
4. If southern states seceded from the Union, then the southern states would form their own government.