China remains the top concern for long-term US national security and tensions over Taiwan have increased steadily over the past several months. Chinese President Xi Jinping used the 20th Congress of the Chinese Communist Party to cement his grip on power – and to make clear where his party stands on its future ambitions, to include the reunification of the self-governing island of Taiwan.    So just how close are China and the US moving toward war over Taiwan?    That's something that Cipher Brief Expert Admiral James Stavridis (Ret.) has been contemplating for some time.  He is the author of 2034: A Novel of the Next World War - that he co-wrote with journalist Elliott Ackerman - played out just how that war might start.