Final answer:
The post-Revolution relationship between Americans and the British evolved from colonial subjects to citizens of an independent nation, transforming into a diplomatic and trade-focused interaction after the War of 1812 with treaties like the Rush-Bagot Agreement.
Step-by-step explanation:
The new relationship declared between Americans and their "British brethren" following the American Revolutionary War and War of 1812 was characterized by a formal separation and the establishment of the United States as a sovereign nation, contrasted from the previous colonial relationship where Americans considered themselves Britons. This was a seismic shift from being subjects of the British Crown to being citizens of an independent country. The new relationship evolved into one of diplomacy and mutual interests, especially after the War of 1812, with subsequent agreements such as the Rush-Bagot Agreement improving trade and foreign relations between the two nations.
The legacy of the American Revolution and the sentiment of unity among Englishmen dissolved with the Declaration of Independence, which cited the refusal of the British to listen to American grievances. Further dissolutions were seen during the War of 1812, as the United States and Great Britain grappled with unresolved issues, leading to new boundaries and the beginnings of a more American identity. However, it wasn't until the post-war agreements that the framework for a long-lasting peace and mutual economic prosperity was truly laid down.