The answer would be dealing with business with other countries. This would include treaties, war, etc.
The Articles of Confederation didn't give the federal government much power, and gave states a lot.
The US system is based on the principles of democracy, that is, the power is with the people, who choose their representatives.
If there is no citizen participation, then the representatives have no incentive to take decisions according to the will of the people, since they don't need to fear not being re-elected.
In this case, some could try to take over the power and establish a dictatorship.
This is called bias.
If you only give evidence to support one side and don't show the facts from the other side, this is being one-sided, which is better known as being biased.