Back in the 1980s, my father, an economist educated at American University, was fond of saying that the difference between the USSR and US is, in the former, dissenters are locked in, and in the latter, they are locked out. In the excellent HBO miniseries Chernobyl—which is set in the deep twilight of the Soviet Empire (the mid-1980s), features prominent British actors, and had its fifth and final episode on Monday, June 3—there's not one...