"[Putin] spiraled into self-aggrandizement and anti-Western zeal, leading him to make the fateful decision to invade Ukraine in near total isolation..."

"... without consulting experts who saw the war as pure folly. Aides and hangers-on fueled his many grudges and suspicions, a feedback loop that one former confidant likened to the radicalizing effect of a social-media algorithm.... The Russian military, despite Western assumptions about its prowess, was severely compromised, gutted by years of theft.... Once the invasion began, Russia squandered its dominance over Ukraine.... It relied on old maps and bad intelligence to fire its missiles, leaving Ukrainian air defenses surprisingly intact.... Russian soldiers, many shocked they were going to war, used their cellphones to call home, allowing the Ukrainians to track them and pick them off in large numbers."

From an excellent NYT article, "Putin's War: The Inside Story of a Catastrophe."

"And Russia’s armed forces were so stodgy and sclerotic that they did not adapt, even after enduring huge losses on the battlefield.... [It] seized more territory than it could defend, leaving thousands of square miles in the hands of skeleton crews of underfed, undertrained and poorly equipped fighters. Many were conscripts or ragtag separatists from Ukraine’s divided east, with gear from the 1940s or little more than printouts from the internet describing how to use a sniper rifle, suggesting soldiers learned how to fight on the fly.... Now, Mr. Putin’s fractured armies often function like rivals, competing for weapons and, at times, viciously turning on one another. One soldier recounted how the clashes became violent, with a Russian tank commander deliberately charging at his supposed allies and blowing up their checkpoint."