I honestly hope they don't get mired in this mess. Hopefully, they'll go after Aleph (formerly Aum Shinryko), and not get involved in any land wars. I'm sure China would be the first of many countries to yell about the "warmongering" Japanese going back to their imperial tendencies.
I don't see why anyone would want to join a war that is never-ending and unwinnable. There are always going to be people who don't like the USA or their own country's government/way of life and will commit acts of terrorism to try and change things. You can never eliminate terrorism and make everyone like you. This whole "War on Terror" seems to just be an excuse to do things that the government otherwise might not get away with. But since we are "at war" we can go bomb countries, have wars and all sorts of other fun stuff to make us "safe" and protect our "freedoms" while our freedoms our slowly eroded away to make us "safe" from the terrorists.