The important points that are given to prove the main point are essential

cruel, heartless

explanation:

the constitution gives congress the power to regulate commerce "among" the several states.

i believe it would influence their own way of understanding things. it shall be a foundation where they can draw or start an argument.   historians are also  scientists that  have their tools of analysis and expertise to unlock a variety of difficulties such as relationships of man, origin, politics, economy, and culture. based on facts and understanding on these areas, they may shade light to extract ideas and develop options to validate a hypothesis or debunk it.

it required the unanimous approval of the states before the congress could enact any measure.