Final answer:
The major defect in the national government established by the Articles of Confederation was that it lacked power.
Step-by-step explanation:
A major defect in the national government established by the Articles of Confederation was that it lacked power. Under the Articles, the national government had limited authority and was unable to effectively address important issues and challenges facing the country. For example, it lacked the power to tax, pay down the national debt, raise an army, and regulate commerce among the states. This weakness ultimately led to the need for a stronger government, which was addressed through the development of the Constitution.