Final answer:
The second party system in the United States lasted from 1815 to the early 1850s and was characterized by the dominance of the Democrats and opposition parties. The question of slavery played a significant role in the decline of the second party system.
Step-by-step explanation:
The second party system lasted from 1815 to the early 1850s. It emerged in 1828 with the Democrats campaigning for Andrew Jackson and opposing parties forming to oppose his vision. The question of slavery and its expansion westward ultimately led to the decline and end of the second party system.