I think that the best approach to take with this prompt is to demonstrate how specific sources show the growth of national unity with the emergence of political parties. Documentation and use of sources will be critical with this. The first step is to make sure you have a sufficient number of sources to demonstrate the extent of national unity. Once you are able to do this, you can proceed with the argument and analysis of how national unity was created through political parties.
I would make sure you are able to address significant leaders of the time period and their use of the political party system to construct national unity. The establishment of the Federalist and Republican parties might have divided the nation into political camps, but it can be argued that it brought more people into the political process. At the same time, national unity was forged in how people viewed the strength of their political party. From here, I would focus on how Jackson's campaign for president utilized the political party focus in order to construct a message that more Americans could embrace. The Jacksonian campaign for President focused on political parties including different voices that were previously silenced, representing how political parties can enhance the growth of national unity. In being able to identify how different political leaders in America utilized the political party system to construct national unity, anther path for explaining this prompt is demonstrated.