Commentary It’s hard not to notice that in the United States, political arguments frequently turn on questions that, in other democracies, nobody talks about. What are the powers of the legislature? What may the executive do? What can the states do without begging permission from the national government? Why can’t an idea popular with the public become a law? For these and other questions, the answer will always involve the American Constitution, a document more than two centuries old that has been amended (not counting the Bill of Rights) only 17 times. In the wake of the 2016 election—in which, not for the first time, a candidate who lost the popular election entered the White House anyway—talk about the Constitution’s “defects” has become more insistent. Why can’t America be more like other countries? Do you worry about fracking? Boris Johnson was worried, so he banned it, because he is the …