Final answer:
After the American Revolution, the 13 states formed a government under the Articles of Confederation, which created a league of friendship but was too weak to be effective.
Step-by-step explanation:
Immediately after the American Revolution, the 13 states established the Articles of Confederation as their government. This first national constitution formed a 'firm league of friendship' among the states and was meant to coordinate efforts for the common defense and ensure mutual and general welfare. However, it soon became evident that the Articles created a government lacking sufficient power to enforce laws, impose taxes, or effectively conduct foreign affairs. The fundamental weakness of the government under the Articles necessitated the development of a new constitution, which led to the drafting of the current United States Constitution.