Mostly. No matter much you trim your certificate chain, there's nothing preventing Google/your bank/Amazon/etc from sharing their private key with, say, Uncle Sam. However, the backdoor admin access that the gov't gets to sites like TwitterFace and Gmail probably makes that a pointless effort.
Confidentiality/Authenticity are pretty much impossible to guarantee unless you control everything on both ends.
Makes you wonder what actually happened with TrustWave (there's obviously more to it than "Oh, this was an ethical dilemma so we stopped."). Probably their customer found a way into the intermediate CA private key and was being naughty with it.
What I think sparked Mozilla is TrustWave's claim that this kind of thing is widespread and commonplace among CA's. That's shouldn't surprise anyone, though.
Chrome already has a mechanism to detect a MITM for Google's servers by embedding those servers' public keys into Chrome itself.
Of course, that doesn't stop a company from placing locally-trusted rogue certificates on computers they control, overriding Chromes public-key pinning check. But it means that they can't MITM a connection from your personal laptop when you're on their network.
They can do public-key pinning like Chrome does (for example, they embed the "mail.google.com" public key into Chrome itself, and verify that it's the certificate you're TLS'ing to.
Mostly. No matter much you trim your certificate chain, there's nothing preventing Google/your bank/Amazon/etc from sharing their private key with, say, Uncle Sam. However, the backdoor admin access that the gov't gets to sites like TwitterFace and Gmail probably makes that a pointless effort.
Confidentiality/Authenticity are pretty much impossible to guarantee unless you control everything on both ends.