I nominate Recep Tayyip Erdogan, president of Turkey, as the most inconsistent, mysterious, and therefore most unpredictable major politician on the world stage. His victory in a referendum last Sunday formally bestows him with near-dictatorial powers that leave Turkey, the Middle East, and beyond in a greater state of uncertainty than ever.Here are some of the puzzles:Mystery #1: Holding the referendum. The Turkish electorate voted on April 16 in a remarkable national plebiscite that dealt not with the usual topic – floating a bond or recalling a politician – but with fundamental constitutional changes affecting the very nature of their...