An editorial on Russia’s crackdown on protests in the Wall Street Journal today puts the Yukos affair into context: The pivotal event was Yukos. Before this case, it was hard to imagine that the Kremlin could ever go so far as to use a tax evasion case to destroy Russia’s richest man, Mikhail Khodorkovsky, and its biggest oil company, Yukos. But it did just that — with impunity. Yukos’s choicest bits were sold to a state-owned Russian oil company for a song, in the first of many steps by the Kremlin to reassert its control over the energy sector. Mr. Khodorkovsky, a Putin rival, is serving a 10-year sentence in a Siberian camp. In subsequent years, the courts were instrumental in forcing Royal Dutch Shell out of a multi-billion dollar energy exploration project and to pressure other international majors.