This sentence would probably be a citation in APA style. Citations on research papers are very important since they give due credit to the original owner of the statement. Statements that don't have citations tells the readers that those statements are of the researcher/s alone which would be a problem for them if found out that it wasn't theirs to begin with. This would result to a work of plagiarism which is a grave sin in constructing research papers and is more equated with the act of stealing.
Answer:
The author helps us to understand how in the early 1800s the central US region was still adapting to the government and the new federalist structure that was being established.
Explanation:
The author shows that the changes in the regions that were no longer a colony, to become a federal state, needed a lot of adaptation and patience, but that the cooperation of individuals and the perseverance of great political names, such as Thomas Jefferson and others, was efficient. This adaptation to federalism allowed the regions to be gradually strengthened, but managed to achieve stability and effectiveness.