Final answer:
Tecumseh's confederation floundered due to the defeat at the Battle of Tippecanoe, the death of Tecumseh, and the American control of the Great Lakes.
Step-by-step explanation:
Tecumseh's confederation floundered due to several factors. One of the main causes was the defeat at the Battle of Tippecanoe in 1811. Tenskwatawa, Tecumseh's brother and spiritual leader, launched an attack but was defeated, leading to the destruction of Prophetstown, the center of the Indian alliance. This event weakened the confederation and undermined Tenskwatawa's credibility.
Furthermore, the death of Tecumseh at the Battle of the Thames in 1813 dealt a major blow to the confederation. Without his strong leadership, the confederation lost momentum and many tribes returned home, leaving only some Indians to continue fighting for the British.
Lastly, the American control of the Great Lakes after winning the Battle of Lake Erie in 1813 further isolated the confederation and shifted the focus of the war to the south. These factors combined ultimately led to the downfall of Tecumseh's confederation.