Dred Scott v. Sandford (1857) was the Supreme Court decision in which Chief Justice Roger Taney ruled that African Americans were not citizens and could not sue in federal court, and that Congress had no power to ban slavery in the territories, voiding the Missouri Compromise and accelerating the path to Civil War.
Dred Scott was an enslaved man who sued for his freedom after living with his enslaver in free territory (Illinois and the Wisconsin Territory). In 1857, Chief Justice Roger Taney's Court handed down a sweeping decision against him with three big rulings. First, African Americans, whether enslaved or free, were not citizens of the United States and had no standing to sue in federal court. Second, Congress had no constitutional power to ban slavery in the territories. Third, that meant the Missouri Compromise of 1820 was unconstitutional, only the second time the Court had ever struck down a federal law.
For the AP exam, the decision matters less as a legal case and more as a political earthquake. The CED (KC-5.2.II.B.ii) lists Dred Scott alongside the Kansas-Nebraska Act as attempts by courts and national leaders to settle slavery in the territories that 'ultimately failed to reduce conflict.' Instead of calming things down, the ruling convinced many Northerners that a 'Slave Power' controlled the federal government, energized the new Republican Party, and made compromise look impossible. It also nationalized racial inequality by writing the denial of Black citizenship into constitutional law.
Dred Scott sits at the heart of Topic 5.6 (Failure of Compromise) and learning objective APUSH 5.6.A, which asks you to explain the political causes of the Civil War. The decision is one of the clearest pieces of evidence that institutional fixes (compromises, popular sovereignty, court rulings) kept failing. It also feeds Topic 5.12's comparison work, because the 14th Amendment's citizenship clause directly reversed it, a perfect change-over-time pairing. Looking backward, it connects to Topic 4.12 and APUSH 4.12.A, since free African Americans had spent decades building communities and pressing legal and political claims to citizenship, and Dred Scott slammed that door shut at the federal level. Thematically, it's prime material for Politics and Power (POL) and the failure of national institutions to contain sectionalism.
Keep studying APUSH Unit 5
Missouri Compromise (Unit 4)
Taney's ruling declared the Missouri Compromise unconstitutional, erasing the 36°30′ line that had managed sectional tension for almost 40 years. Dred Scott is essentially the moment the Court told Congress its compromise toolkit was illegal.
14th Amendment (Unit 5)
The 14th Amendment (1868) defined citizenship as belonging to anyone born in the United States, which directly overturned Dred Scott's denial of Black citizenship. This before-and-after pair is gold for continuity-and-change essays in Topic 5.12.
Abraham Lincoln (Unit 5)
Dred Scott handed Lincoln and the Republicans their central argument, that slavery was being nationalized by a pro-slavery federal government. The decision sharpened the Lincoln-Douglas debates and helped propel Lincoln to the presidency in 1860.
Abolitionist Movement (Units 4-5)
Abolitionists pointed to Dred Scott as proof that the political system would never end slavery on its own. The ruling radicalized moderates and pushed antislavery politics from containment toward confrontation.
Multiple-choice questions usually pair an excerpt (often from Taney's opinion or a Northern newspaper reaction) with stems asking what principle the decision asserted, how it affected sectional tensions, or how it shifted the balance of federal and state power over slavery. You need to do more than recall the verdict. Be ready to explain causation, meaning how Dred Scott destroyed the credibility of compromise, boosted the Republican Party, and pushed the nation toward war. No released FRQ has used the case verbatim as a prompt, but it's high-value evidence for any LEQ or DBQ on the political causes of the Civil War (APUSH 5.6.A) or on continuity and change in African American citizenship from the early republic through Reconstruction.
Both are infamous Supreme Court cases about race, but they belong to different periods and do different things. Dred Scott (1857, Period 5) denied Black citizenship entirely and protected slavery in the territories before the Civil War. Plessy (1896, Period 6/7) came after the 14th Amendment had established Black citizenship and instead upheld segregation under 'separate but equal.' Quick check for the exam: Dred Scott is about citizenship and slavery; Plessy is about segregation.
In 1857, Chief Justice Roger Taney ruled that African Americans were not citizens and therefore could not sue in federal court.
The decision held that Congress could not ban slavery in the territories, which made the Missouri Compromise unconstitutional.
Per the CED, Dred Scott is a textbook example of an attempt to resolve slavery in the territories that 'failed to reduce conflict' (KC-5.2.II.B.ii).
The ruling energized the Republican Party and convinced many Northerners that a 'Slave Power' controlled the federal government.
The 14th Amendment (1868) overturned Dred Scott by guaranteeing birthright citizenship, making the case a key 'before' point in change-over-time arguments.
Use Dred Scott as evidence for the political causes of the Civil War (APUSH 5.6.A), not just as a standalone court case.
In 1857, the Supreme Court ruled that African Americans were not U.S. citizens and could not sue in federal court, and that Congress had no power to ban slavery in the territories. That second part struck down the Missouri Compromise of 1820.
Not by itself, but it was a major political cause. The CED groups it with the Kansas-Nebraska Act as failed attempts to settle the slavery question, and it destroyed faith in compromise, fueled the Republican Party, and deepened the sectional split that led to war by 1861.
Dred Scott (1857) denied Black citizenship and protected slavery in the territories before the Civil War. Plessy (1896) came after the 14th Amendment made African Americans citizens and instead upheld segregation under 'separate but equal.' Different periods, different issues.
The 13th Amendment (1865) abolished slavery, and the 14th Amendment (1868) guaranteed citizenship to anyone born in the United States, directly reversing Taney's ruling that African Americans could never be citizens.
Taney argued that African Americans, free or enslaved, were not citizens under the Constitution and therefore had no standing in federal court. Exam questions often quote this reasoning and ask what principle of racial inequality it asserted.