It actually doesn't matter. They are talking about comprimising the servers. The government has the power to force a backdoor (remember Lavabit?). All Whatsapp has to do is update their client, and all the beautiful encryption schemes are ruined.
If you need a truly secure communication system, it has to be open source and self-hosted. You still have to trust the hardware though.
To expand on this argument a bit, if you think the Government/Whatsapp are specifically out to get you (eg. willing to mount an active attack against you specifically), then WhatsApp is propably the wrong messenger for you.
If on the other hand you want a reasonably secure Messenger that you can use to chat privately with everybody and their Grandma then maybe you should not expect that it does super complex security thingys that 99% of its users just don't care about and don't want to be bothered with..
If you need a truly secure communication system, it has to be open source and self-hosted. You still have to trust the hardware though.