Proposals included:<ul id="mwBKY"><li id="mwBKc">The <a rel="mw:WikiLink" href="./Wilmot_Proviso" title="Wilmot Proviso" id="mwBKg">Wilmot Proviso</a>... by @wikipedia

Proposals included:The Wilmot Proviso banning slavery in any new territory to be acquired from Mexico, not including Texas, which had been annexed the previous year. Passed by the United States House of Representatives in August 1846 and February 1847 but not the Senate. Later an effort to attach the proviso to the Treaty of Guadalupe Hidalgo also failed.
Failed amendments to the Wilmot Proviso by William W. Wick and then Stephen Douglas extending the Missouri Compromise line (36°30′ parallel north) west to the Pacific Ocean , allowing slavery in most of present-day New Mexico and Arizona, southern Nevada, and Southern California, as well as any other territories that might be acquired from Mexico. The line was again proposed by the Nashville Convention of June 1850.
Popular sovereignty, developed by Lewis Cass and Douglas as the eventual Democratic Party position, letting each territory decide whether to allow slavery.
William L. Yancey's "Alabama Platform", endorsed by the Alabama and Georgia legislatures and by Democratic state conventions in Florida and Virginia, called for no restrictions on slavery in the territories either by the federal government or by territorial governments before statehood, opposition to any candidates supporting either the Wilmot Proviso or popular sovereignty, and federal legislation overruling Mexican anti-slavery laws.
General Zachary Taylor, who became the Whig candidate in 1848 and then President from March 1849 to July 1850, proposed after becoming President that the entire area become two free states, called California and New Mexico, but much larger than the eventual ones. None of the area would be left as an unorganized or organized territory, avoiding the question of slavery in the territories.
The Mormons' proposal for a State of Deseret, incorporating most of the area of the Mexican Cession but excluding the large non-Mormon populations in Northern California and central New Mexico, was considered unlikely to succeed in Congress, but nevertheless in 1849 President Zachary Taylor sent his agent John Wilson westward with a proposal to combine California and Deseret as a single state, decreasing the number of new free states and the erosion of Southern parity in the Senate.