Why did some american leaders call for a stronger national government ?

Assuming you are speaking about when leaders wanted to reform the Articles of Confederation -

The current government was incapable of settling national disputes without any money from taxes. This included many interstate issues, such as taxes on trade and even states denouncing other states. With a reformed federal government, they would be able to step-in and maintain order within the country.

in 342 bc j._c. egypt fell into the hands of the persians, under the reign of nectanebo ii

greek city-states unite in a revolt against the persian empire at the beginning of the fifth century bc. j.-c  

from the year 660 or 659 bc ad, cyrus preached the revolt against the medes to deliver the persians.

is there multiple choice or do you need like an essay answer?