Answer:
The power to tax the states by the Federal government.
Step-by-step explanation:
The articles of confederations provided the states government with somewhat stronger power compared to the central government. This made the central government had very little power to stop the states in case any of them did something that causing problems for other states.
On top of that, the central government also experience difficulties in obtaining funding to pay for proposed programs that created on national scale.
To fix it, Federal government need to possess the power to tax the states. This will allow the federal government to obtain the necessary budget to fund government programs and impose punishment to the states that were causing problems.