AP U.S. History / Period 4: 1800–1848
Lesson
Expansion, reform, and the slavery question
Reformers argued about morals while the map kept growing.
Learning goals
- Explain why westward expansion reopened conflict over slavery.
- Give one example of a reform movement and one limit it faced.
Explanation
Each new territory raised a constitutional and moral question: would slavery expand with the country? Compromises tried to keep a political balance, but they did not settle the deeper conflict between an expanding slave economy and a growing free-labor North.
Reformers organized around temperance, education, women's rights, and abolition. Some used churches and print; some used petitions and conventions. They did not speak with one voice. Abolitionists challenged slavery directly, while many other reformers left it aside. When you study reform, name the goal and the people the movement still ignored.
Key terms
- abolition. The movement to end slavery, ranging from gradual plans to immediate emancipation.
- sectionalism. Political loyalty organized around regional interests, especially over slavery's expansion.
Common mistakes
- Treating all reformers as abolitionists.
- Explaining expansion only as adventure and skipping Native dispossession and slavery.
Practice
Original Marlow Works items. Check the answer explanation after you try.
Which weakness of the Articles of Confederation most directly encouraged support for a new constitution in the 1780s?
Original Marlow Works item — not a College Board question.
Take your time—this is practice, not a test.
Answer explanation
Why did adding territory make national politics less stable?
Answer. New land forced Congress to decide whether slavery would expand, which split parties and regions.
Geography became a slavery question, not just a map question.
Related resources
External links with reuse status. Marlow Works is independent and does not copy restricted exam or textbook material.
Official / link only
AP U.S. History course page
Official nine-period framework, skills, and exam updates.
College Board · All rights reserved · accessed 2026-10-01
Open sourceCC BY — attribution required
U.S. History (Open Textbook Library)
Open U.S. history textbook for chronology and institutions background.
Open Textbook Library listing · CC BY · accessed 2026-10-01
Open source