Unstable because of the threats of terror, weapons of mass destruction, the spread of global disease and a sense that we are vulnerable to it in a way that we weren't not so many years ago.
不稳定的原因是多样的：恐怖袭击的威胁、 大规模杀伤性武器、全球范围内的疾病扩散、 以及一种史无前例的脆弱感。