I wrote discussing plausible deniability for public postings:
But for your suggested applicatoin -- plausible deniability for `speaking truth to kings' -- it works fine, because that's the point, plausible deniability against well resourced attackers (you are in trouble if well resourced attackers are interested in you anyway), but some value to the signature for low resourced attackers.
Other ways to provide plausible deniability is to not sign public posts, and to use non-transferable signatures for private email.
I missed from this list of approaches for plausible deniability the canonical cypherpunks approach: post anonymously :-) The other way is perhaps to have shared identities, such as Monty Cantsin claimed to be, and such as perhaps Toto has been on occasion. Adam -- print pack"C*",split/\D+/,`echo "16iII*o\U@{$/=$z;[(pop,pop,unpack"H*",<> )]}\EsMsKsN0[lN*1lK[d2%Sa2/d0<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<J]dsJxp"|dc`