Vladimir Putin has taken to comparing himself to some of his czarist predecessors, invoking their military triumphs. In June, he praised Peter the Great for “taking back and reinforcing” territory in the Baltics in the Great Northern War in the 18th century. But as Putin’s effort to conquer parts of Ukraine slogs into its sixth month, some historians feel he more closely resembles Nicholas II, whose 1904-1905 war against Japan was an unmitigated disaster. The parallels between the two conflicts are undeniable. Just as Nicholas underestimated his Japanese adversary, so did Putin, who was convinced that his invasion of Ukraine...