How the US handles diplomacy with Taiwan will determine what direction the Japanese military takes. Japan is already the 4th largest military in the world despite the fact that technically aren't suppose to have a military. It would take Japan about a week to develop nuclear weapons and a matter of months to convert their existing military into a more aggressive force.
The US is suppose to handle the regional conflicts so that Japan doesn't have to rewrite their constitution to allow itself to have a standing military again. If the US stood back and did nothing while Taiwan was invaded Japan would be well within it's rights to cancel alliances with the US and kick all of the soldier's out of Okinawa. We'd lose all credibility in the pacific which, lets be honest, is the biggest reason to have a hegemonic naval force at this point.
China would need assurances that the US wouldn't intervene, because if the try to take Taiwan and fail, it might be the end of the leadership in China.
How the US handles diplomacy with Taiwan will determine what direction the Japanese military takes. Japan is already the 4th largest military in the world despite the fact that technically aren't suppose to have a military. It would take Japan about a week to develop nuclear weapons and a matter of months to convert their existing military into a more aggressive force.
The US is suppose to handle the regional conflicts so that Japan doesn't have to rewrite their constitution to allow itself to have a standing military again. If the US stood back and did nothing while Taiwan was invaded Japan would be well within it's rights to cancel alliances with the US and kick all of the soldier's out of Okinawa. We'd lose all credibility in the pacific which, lets be honest, is the biggest reason to have a hegemonic naval force at this point.
China would need assurances that the US wouldn't intervene, because if the try to take Taiwan and fail, it might be the end of the leadership in China.