Could Bitcoin be shut down like Liberty Reserve because of unethical or illegal use?

Bitcoin is a protocol that is running in a distributed peer-to-peer environment, you can't exactly shut it down, unless you can have everyone who runs a bitcoin node to shut down. The currency element just happens to be the very first app that is build on top of the Bitcoin protocol. The currency could fail, but the underlying Bitcoin protocol will still prevail, we could possibly invent something else on this protocol.

You can't really shut down the US Currency Notes, because they are being used for illegal purposes, likewise, I don't believe you can shutdown Bitcoin money on the same argument.