Which political party dissolved after the War of 1812, leading to a period of one-party rule?

The Federalist Party dissolved after the War of 1812, leading to a significant shift in the American political landscape. This dissolution occurred for several reasons, particularly due to the party's opposition to the war and the perception that it had become increasingly irrelevant following the war’s conclusion. The Federalists were seen as unpatriotic, especially after the Hartford Convention, where some party members discussed New England’s potential secession from the Union if their interests were not met. This perception, coupled with the rising popularity of the Democratic-Republican Party, allowed the latter to dominate national politics for a time.

The period following the War of 1812 is often referred to as the "Era of Good Feelings," characterized by a lack of partisan conflict since the Democratic-Republicans effectively became the only significant national party. The absence of serious opposition allowed them to pursue their policies without substantial political challenge, marking a unique moment in early American political history.