I'm not sure that there is currently an organized attempt to bring down bitcoin.  From what I understand, the Mt. Gox hacking was an attempt to steal bitcoins.

That being said, there will most definitely be an organized government effort to bring down bitcoin.  Probably won't happen for another couple of years because the government is slow and reactive rather than proactive, but it will happen as long as bitcoin continues to grow in popularity and use.  The people who run our government can't stand that something might be outside of their control.  Nothing makes them angrier.