Final answer:
The cooperation of political opponents after the War of 1812 signified the OC. Era of Good Feelings, characterized by strong patriotism and the desire for a united front in politics and national growth.
Step-by-step explanation:
The working together of political opponents during the aftermath of the War of 1812 was a sign of the OC. Era of Good Feelings. This period reflected a sense of national purpose and a desire for unity among Americans in the aftermath of the War of 1812.
Patriotic sentiments ran high, and there was generally one-party rule, which saw the decline of the Federalists and dominance of the Republicans.
During this era, crucial financial and transportation system developments were made, Congress chartered the Second Bank of the United States, approved a protective tariff to foster economic independence, and the Supreme Court made decisions that broadened federal power and promoted economic development.
The Era of Good Feelings saw a number of major developments, including the emergence of new political leaders who favored national growth, such as John C. Calhoun, Henry Clay, and Daniel Webster, who fostered the market revolution with their nationally-minded programs.
Despite the patriotic unity, certain tensions and debates over tariffs, bank regulations, internal improvements, slavery extension, and Indian removal indicated the emergence of new political challenges.
In particular, the decisions of Dartmouth College v. Woodward, McCulloch v. Maryland, and Gibbons v. Ogden played significant roles in shaping the nation's future in state-federal relations and the economy.