I'm sure YOU back her up though when she has to discipline them, right? That's an important part of discipline. Parents need to agree and not fight about the discipline in front of their kids (who are masters at manipulation--smile). Sounds like you have a treasure therer.
Of course.
My wife succeeds so spectacularly, I think, because she has always modeled perfectly approriate behavior, self-control, and discipline in her own life without being harsh and while remaining cheerful and pleasant. Our sons have amazingly high regard and respect for her. Our two oldest are now married and, to their credit, they sought out and married women similar in temperament to their mother.
I couldn't be more blessed or happier. My boys are all good, obedient, thoughtful, and successful because of their mother. I am one incredibly lucky guy.