It’s been a year of tumult and chaos in world politics. In Japan, a national poll selected the kanji character sai, meaning disaster, as best reflecting the national mood. Perhaps 2019 will bring better news. In the meantime, here are the states, individuals, institutions and ideas that were 2018’s biggest losers. Next week: the winners.

• China’s Belt and Road Initiative. In 2018 Beijing began to learn how hard it is to build an international system. The BRI isn’t only a massive infrastructure project intended to build an...