The apparent victory of Hong Kong protesters and a mini-thaw taking place in Russia are interesting departures from the usual practice of two regimes known to have no reverse gear. Could they have decided to learn a technique one student of authoritarianism has dubbed "contained escalation"?

The communist government of mainland China has been whittling away at Hong Kong's British-style liberties for years, and protests were routinely ignored. The so-called Umbrella Revolution of 2014 — a series of protests against a plan to have candidates for the role of Hong Kong's chief executive screened by the mainland — resulted in the preservation of an even more restrictive electoral system. And last April, nine of the movement's leaders were convicted of "conspiring" and "inciting" to cause a public nuisance. Even in relatively liberal Hong Kong, the regime that crushed the Tiananmen Square protests didn't step back in the face of popular indignation.

This time it's different — the (much more numerous) protesters have forced pro-Beijing Chief Executive Carrie Lam to shelve a bill that would allow extradition from Hong Kong to the mainland, which would have dealt a major blow to the special economic region's judicial independence. And Lam has promised no arrests, too.