The Northerners didnt want Texas to be annexed because it would increase the area and politcal strength of slave power. AnswerParty!
Politics of the United States
Slavery in the United States
The United States is a federal constitutional republic, in which the President of the United States (the head of state and head of government), Congress, and judiciary share powers reserved to the national government, and the federal government shares sovereignty with the state governments.
Slavery in the United States for this article refers to the legal institution that existed in the United States of America in the 18th and 19th centuries. Slavery had been practiced in British North America from early colonial days, and was firmly established by the time of the United States' Declaration of Independence in 1776. After this, there was a gradual spread of abolitionism in the North, while the rapid expansion of the cotton industry from 1800 caused the South to identify strongly with slavery, and attempt to extend it into the new Western territories. Thus slavery polarized the nation into slave states and free states along the Mason-Dixon Line, which separated Maryland (slave) and Pennsylvania (free).
Although the international slave trade was prohibited from 1808, internal slave-trading continued apace, and the slave population would eventually peak at four million before abolition. Of all 1,515,605 free families in the fifteen slave states in 1860, nearly 400,000 held slaves (roughly one in four, or 25%), amounting to 8% of all American families. By the time of the United States founding, even through some free persons of color were present, the status of slave was largely limited almost entirely to Africans and those of African decent, creating a system and legacy in which race played an influential role.
Bleeding Kansas, Bloody Kansas or the Border War was a series of violent political confrontations involving anti-slavery Free-Staters and pro-slavery "Border Ruffian" elements, that took place in the Kansas Territory and the neighboring towns of Missouri between 1854 and 1861. At the heart of the conflict was the question of whether Kansas would enter the Union as a free state or slave state. As such, Bleeding Kansas was a proxy war between Northerners and Southerners over the issue of slavery in the United States. The term "Bleeding Kansas" was coined by Horace Greeley of the New York Tribune; the events it encompasses directly presaged the American Civil War, as well as the future relationship between Kansas and Missouri.
Congress had long struggled to balance the interests of pro- and anti-slavery forces. The events later known as Bleeding Kansas were set into motion by the Kansas–Nebraska Act of 1854, which nullified the Missouri Compromise and instead implemented the concept of popular sovereignty. An ostensibly democratic idea, popular sovereignty stated that the inhabitants of each territory or state should decide whether it would be a free or slave state; however, this resulted in immigration en masse to Kansas by activists from both sides. At one point, Kansas had two separate governments, each with its own constitution, although only one was federally recognized. On January 29, 1861, Kansas was admitted to the Union as a free state, less than three months before the Battle of Fort Sumter which began the Civil War.
Southern United States
The Slave Power (often called the "Slaveocracy") was a term used in the United States ca. 1840–1865 to denounce the political power of the slaveholding class in the South. The argument was that this small group of rich men had seized political control of their own states and were trying to take over the national government in an illegitimate fashion in order to expand and protect slavery.
The main issue expressed by the phrase was distrust of the power of slave-owning oligarchs. Such distrust was shared by many who were not abolitionists; those who were motivated more by a possible threat to the political balance or the impossibility of competing with unwaged slave labor, than by concern over the treatment of slaves. Those who differed on many other issues (such as hating blacks or liking them, denouncing slavery as a sin or promising to guarantee its protection in the Deep South) could unite to attack the "slaveocracy." The "Free Soil" element emphasized that rich slave owners would move into new territory, use their cash to buy up all the good lands, then use their slaves to work the lands, leaving little opportunity room for free farmers. By 1854 the Free Soil Party had largely merged into the new Republican party
The Southern United States—commonly referred to as the American South, Dixie, or simply the South—is an area comprising the southeastern and south-central United States. The region is known for its culture and history, having developed its own customs, musical styles and varied cuisines that have helped distinguish it in some ways from the rest of the United States. The Southern ethnic heritage is diverse and includes strong European (mostly English, Scotch-Irish and Scottish), African, and some Native American components. Several Southern states (Virginia, North Carolina, South Carolina, and Georgia) were English Colonies that sent delegates to sign the Declaration of Independence and then fought against the English along with the Northern Colonists during the Revolutionary War. The basis for much Southern culture derives from the pride in these states being among the 13 original colonies (and much of the population of the South had fore-fathers who emigrated west from these colonies). Manners and customs reflect the early population of the South's relationship with England as well as that of Africa and to some extent the native populations.
Some other aspects of the historical and cultural development of the South have been influenced by an early support for the doctrine of states' rights, the institution of slave labor on plantations in the Lower South; the presence of a large proportion of African Americans in the population; and the legacy of the Civil War and Reconstruction Era, as seen in thousands of lynchings (mostly from 1880 to 1930), the segregated system of separate schools and public facilities known as "Jim Crow", that lasted until the 1960s, and the widespread use of poll taxes and other methods to frequently deny blacks of the right to vote or hold office until the 1960s. In more modern times, however, the South has become the most integrated region of the country and race-relations on par with those elsewhere. Since the late 1960s blacks have held and currently hold many high offices, such as mayor and police chief, in many cities such as Atlanta and New Orleans.]better source needed[