[quote=@Claw2k11]
[@Blekee]
It wasn't much of a civil war if the armies sent against him joined him instead. It's like when Napoleon returned from Elba and every French army sent against him joined him instead.
[/quote]

That part might just, and I'm simply speculating here, because Napoleon had by that point already ruled France as Emperor for over 10 years, and actually proven himself a capable leader in all aspects. 

By comparison, the only things that the last emperor of Mexico managed to pull off, was because of said frenhcman's grandson (I think), Napoleon III's support to him.