That's it. That's the basis for the Constitution. We could have called ourselves the "Mutual Protection Society" instad of the "United" states, but the states considered themsleves sovereign, they insisted on keeping the "s" at the end of "State" for a reason.
The founders argued for YEARS to give us a LIMITED federal government with strictly separated and enumerated powers. EVERYTHING else remained in the hands of the states. Everything.
The federal government could not establish a NATIONAL religion, but the states certainly could establish one for themselves. The vast majority of states had specific religious requirements for their own elected officials.
Even Madison and Hamilton argued that we didn't need a Bill of Rights, both arguing that unless a right to control something had been DELEGATED to the federal government, it was beyond their reach.
And the founders also went out of their way to eliminate the word "perpetual" from the "Constitution". That word was used 5 times in the articles, yet nothing to indicate a permanent relationship was included. Considering that the young country had seceded from Britain and now was seceding from the Articles, it was ludicrous to perpetuate the myth of permanence. Madison just considered this new government another "experiment".
Simple - protection form common enemies - and separate state governments to continue. Consider Article I, section 4"
The Congress shall assemble at least once in every Year, and such Meeting shall be on the first Monday in December, unless they shall by Law appoint a different Day.Meet at least once a year, and then - starting in DECEMBER! A whole MONTH to conduct all the necessary business for the federal government. < /sarcasm >
Who was it that said by design governments consume power infinitely?