Conflict intensified as the nation expanded westward. Each new territory raised the question whether slavery would expand and how that decision would affect sectional power in Congress. The Missouri Compromise, Compromise of 1850, and Kansas-Nebraska Act attempted political settlements but did not resolve the moral and constitutional struggle. The Fugitive Slave Act of 1850 also nationalized enforcement by compelling federal participation in recapture, provoking resistance in parts of the North and making slavery harder to treat as a distant regional institution. Abolitionists used petitions, newspapers, litigation, and organizing; slaveholders demanded stronger protection for property claims; and free Black communities challenged both slavery and discriminatory law.

In Dred Scott v. Sandford (1857), the Supreme Court held that Scott was not a citizen entitled to sue in federal court and declared Congress lacked authority to prohibit slavery in the territories. The decision deepened sectional conflict and illustrates that judicial review can entrench injustice as well as protect rights. The Civil War transformed the dispute from recurring compromise into a struggle over Union and emancipation. President Lincoln's Emancipation Proclamation freed enslaved people in areas in rebellion as a war measure, but it did not abolish slavery everywhere.

Permanent constitutional change required amendment. The Thirteenth Amendment abolished slavery, the Fourteenth constitutionalized national citizenship and limits on state government, and the Fifteenth prohibited specified racial discrimination in voting. Together they altered the federal-state balance and supplied Congress enforcement authority. Reconstruction also shows why formal law and lived power can diverge. Federal troops, the Freedmen's Bureau, civil-rights statutes, and newly enfranchised Black voters supported new governments and public institutions. Violent resistance, restrictive Black Codes, and later withdrawal of sustained federal enforcement narrowed those gains. The amendments survived when political commitment weakened, allowing later movements and courts to invoke their text against Jim Crow. The conflict therefore operated at three levels: national authority over slavery, individual status and rights, and the capacity to enforce new rules against resistant governments and private violence. War and amendment settled secession and abolition, but not every dispute over equal citizenship. The original Constitution accommodated slavery; the Emancipation Proclamation was a wartime executive measure of limited geographic reach; the Thirteenth Amendment abolished slavery throughout the nation.

Video lesson: Discrimination: Crash Course Government and Politics #31