Final answer:
The War of 1812 concluded troubled diplomacy through events like the impracticality of impressment, led to the demise of the Federalist Party post the Hartford Convention, and broke the power of American Indians, exemplified by Tecumseh's death, thereby enhancing American self-confidence and expansionism.
Step-by-step explanation:
War of 1812 and Its Consequences
Professor Hickey believes that the War of 1812 resolved many years of troubled diplomacy.
One example prior to the War of 1812 is the practice of impressment, where the British navy would forcibly recruit American sailors under the pretext that they were deserters from the British navy, ignoring United States sovereignty.
The War of 1812 led to the demise of the Federalist Party, as their opposition to the war and proposals such as those made at the Hartford Convention, where some members suggested secession, made them appear unpatriotic once the war concluded with American success.
This effectively ended the party's influence in American politics. The outcome of the war weakened the position of American Indians, an example being the death of Tecumseh and the consequent collapse of the Native American coalition he had led against American expansion.
This strengthened national self-confidence and paved the way for westward expansionism.