Final answer:
The Era of Good Feelings was defined by a renewed sense of nationalism following the War of 1812, marked by President Monroe's efforts to unify the nation and economic strategies to promote national growth.
Step-by-step explanation:
One defining characteristic of the Era of Good Feelings was a renewed sense of nationalism throughout the United States. This period, which directly followed the War of 1812, was marked by the country's recovery from war and a sense of national unity under one political party. President James Monroe's good-will tours and his nearly unanimous reelection in 1820 exemplified the nationalistic spirit of the era. Strategies such as the chartering of the Second Bank of the United States, the implementation of a protective tariff, and the fostering of economic development under the Supreme Court's decisions, underscored the harmonious direction which the country embraced during this time.