The Framers who created the United States Constitution chose the idea of Federalism because they wanted a government that was able to unify a belief within the states without diminishing each states' ability to control itself. Federalism made the most sense because it allowed the states to be controlled by the government while still being able to control their own affairs.
The majority of the Framers of the U.S. Constitution were very distrusting of government operations and the way that governments worked to take away power from the people, but they understood that a government system was necessary for a nation to function properly.
The Framers did not want the government to have complete control of the people, but they wanted the people to be able to have a governing body. The use of Federalism in the U.S. made the most sense because it allowed the government to set rules and standards for citizens while not becoming too much of a power with the use of checks and balances.
Citizens were essentially allowed to govern themselves and choose the people that were in place to govern them. With Federalism, citizens also have the option to decide if an elected official is not doing their job properly or governing the country properly.