Above all, the new autocrats use violence sparingly. This is their key innovation. Hitler took credit for liquidating enemies. Mobutu hanged rivals before large audiences, while Idi Amin of Uganda fed the bodies of victims to crocodiles. Claiming responsibility was part of the strategy: It scared citizens.

The new autocrats are not squeamish — they can viciously repress separatists or club unarmed protesters. But violence reveals the regime’s true nature and turns supporters into opponents. Today’s dictators carefully deny complicity when opposition activists or journalists are murdered. Take the case of the former Ukrainian president Leonid Kuchma. A tape of him reportedly ordering the abduction of a journalist, Georgy Gongadze, who was later found dead, helped fuel the Orange Revolution of 2004, which brought Mr. Kuchma’s rivals to power.

And violence is not just costly — it’s unnecessary. Instead, the new authoritarians immobilize political rivals with endless court proceedings, interrogations and other legal formalities. No need to create martyrs when one can defeat opponents by wasting their time. Mr. Putin’s agents have begun numerous criminal cases against the opposition leader Aleksei A. Navalny: He has been accused of defrauding a French cosmetics company and stealing wood and interrogated about the killing of an elk.