During the second rebellion, the Capitol was still more powerful than all Districts combined. The difference should be even more because of continuous oppression of Districts by the Capitol. Individual Districts were forced to be no-creative labour workforce while the Capitol flourished in every aspect (which includes military research).

The only thing special this time was Mockingjay.

![Mockingjay poster](https://i.stack.imgur.com/LY8ZWm.jpg)

But, she merely acted to unite the Districts. Last time, Districts were already united even to a greater extent. So, she was also not an advantage.

What exactly changed during the second rebellion that the Capitol lost? What prevented Capitol from nuking Districts this time? How did rebellions overcome Capitol's military might?