The Articles of Confederation established a weak central government because Americans were fearful of a strong central government based on their recent experience as British colonists. However, this weak central government had several different problems including:
1) No power to enforce national laws.
2) No power to tax citizens in order to generate revenue.
3) No power to compel representatives from different states to vote on national issues.
4) No executive branch (aka president).
5) No power to force individuals to serve in the military.
All of these flaws made the Articles of Confederation a highly ineffective system.