Contemporary observers called the period of post-war nationalism:

The Era of Good Feelings denoted a period in the political history of the United States that mirrored a feeling of national purpose and a want for solidarity among Americans in the after effects of the War of 1812.

europe would not recognize the confederacy as an independent nation.

interdependence is when all participating groups and individuals depend on each other. if you depend on one anothers goods, you end up trading in order to get the items you're looking for. (for ex: if i have food and you have water, we trade in order to depend on each other to live)