Wanted strong national government
Health insurance is clearly a commercial activity occurring among several States. “power to lay and collect taxes, duties, imposts and excises, to pay the debts and provide for the common defence and general welfare of the United States.”
While you didn't really provide the "following" as the comment above me states, in general, the advantage of secondary sources of primary ones is that they perhaps provide a more objective or even just a broader view on a certain topic. While a primary source of the American civil war would be a letter written by a soldier, a secondary source would be a book that describes more letters taken together and discusses possible information regarding them.
