Does a protracted conflict favour Russia or Ukraine?

The typical war is short. Since 1815, the median duration of wars between states has been just over three months, calculates Paul Poast of the University of Chicago. In 2003 America toppled the government of Iraq in just 20 days. The conflict that Armenia and Azerbaijan fought over the territory of Nagorno-Karabakh in 2020 was over in 44. Yet Russia’s invasion of Ukraine has entered its fifth month, and shows no sign of drawing to a close. “I am afraid that we need to steel ourselves for a long war,” wrote Boris Johnson, Britain’s prime minister, in mid-June. Jens Stoltenberg, nato’s secretary-general, echoed his warning: “We must prepare for the fact that it could take years.”