I have brought this up several times and am still none the wiser.
The ledger needs to say what the sudden death triggers are, be it low NM or the loss of your capital. Although the last shouldn't realy be an automatic loss as Berlin was taken and Prussia didn't lose beacause of this.
I am playing as Austria in the long campaign, with 1.03RC4, and have just had the message that my defeat level of NM will increase by 1 each turn untill the end of the war. I don't know what this defeat level is though
This needs to be stated on the F5 page of the ledger.