You said: "What I understand is that the federal government ONLY enjoys such power as given them explicitly within the Constitution."
Quite right.
I think we are getting mixed up over the limited power of the federal government, which we agree on, and the rights of the people.
The federal consitution did NOT create any rights for its citizens. Those rights pre-existed the Constitution.
Because many anti-constitutionalists feared the power of the new federal goverment--that it might some day try to take away the rigths of the citizens--a Bill of Rights was ratified.
The Bill of Rights did NOT create any new rights. It only memoralized some very important ones, so there could be no mistake later, and left others not mentioned alone.
What you said. Also see my post 49 along the same lines.