That was to make the republic stronger and making a system of roads and canals that would be crucial in order to maintain unity. At the time, there was no system of roads or canals to travel around. There were many benefits to this because many things would go much faster in the country. Trade with other states would be much faster and efficient and messages that needed to be delivered to other state leaders would be received much more quickly and safely. This issue was concerning the internal improvements of the country because without a much needed system of travel, sectionalism would also vulnerable to increase due to the lack of easier communications. Thus, this was another problem that depicted the inaccuracy of the label for this era. .
Nationalism was evident in Document C but, it was a false sense of nationalism. The picture serves to show how many people have misinterpreted the "Era of Good Feelings." The party goers are showing their "good feelings" with a sense of nationalism. This relates to Monroe's Goodwill tour in which toured the Northeast helping to increase nationalism even in New England, which was a federalist state. Although everyone showed a greater sense of nationalism, they still knew the many major problems the country was facing. The reality was that behind the curtains, the country was struggling with sectionalism and many other issues that divided the country.
In Document D, the decision in McCulloch v. Maryland was in favor of the central government and its implied powers rather than giving the states more rights. This is in a sense a nationalist document because it was in favor of the central government rather than states having more power but it still created many problem. If the decision had been in favor of the states, it would have been sectionalist. Marshall in his decision states that the people are the ones who ratified the Constitution and not the states so the people are the ones with power and not the states.