Why do you think the line between the powers of the Federal Government and those of state governments was often not clearly drawn?

Considering the size of America and the number of its states, there is a need for different state laws to encompass different needs and environments. From the creation of the country, it was debatable whether the federal government or central government should control the situation. Because of that lines between state and federal governments are often blurred, as well as the interpretations. The administrations and leaders use different situations to appease both sides.