Joe Biden said Russia was "bent on violence from the start," but James Siebens asks if may be that wasn't so. Maybe the best explanation for Russia's strange invasion is that the buildup was intended as a threat, and the actual invasion was only ordered in frustration after the threat failed to have its desire effect:
Putin’s failure to win concessions through intimidation alone meant that he had to either demobilize his forces or follow through on the tacit threat to invade. The first several days of the invasion demonstrated Russia’s lack of preparedness for “Plan B,” and the initial intention to achieve its aims without large-scale combat. Instead, Putin appears to have hoped for a rapid coup de main by attacking the Ukrainian capital and decapitating the government, apparently relying more on a Ukrainian mutiny and the psychological impact of a sudden attack than on force of arms. He sought to attack Kyiv with a relatively small number of unseasoned and unsupported mechanized forces, and little more than a few hundred paratroopers.
On Feb. 24, a few dozen Russian helicopters and at least 100 airborne forces attacked the Gostomel airfield outside Kyiv, and three helicopters were allegedly shot down. Ukrainian forces led a counterattack to retake the airfield, and after an intense battle, Russian forces eventually secured an airfield that was damaged beyond use. Paratroopers were also sent to capture Kharkiv, along with some light armored vehicles and infantry formations, but without adequate support they were quickly overwhelmed and captured. Russian light vehicles assaulting Kyiv shared a similar fate.
This delusional opening attack, and the apparent lack of preparation for major combat operations across the theater afterwards, evinces a lack of serious consideration of an invasion plan beforehand. Considering the evidence that Russian forces failed to adequately account for the significant practical challenges of equipment maintenance, command and control, operational security, reconnaissance, and intelligence, Russia’s initial invasion verged on lackadaisical. This likely indicates an overconfident expectation that Ukraine would quickly capitulate when faced with an invasion and that Russia would achieve its political goals without serious fighting. While the military capabilities assembled in plain view over the past year ensured that Putin would have the option of invading Ukraine, and persuaded some that he intended to do so, it is difficult to explain away the evident lack of serious planning and preparation for actually executing such a major operation. Attacking Ukraine with less than 200,000 troops may have seemed feasible, but it strains credulity that any military leaders would have agreed to order and execute a major invasion and occupation without having planned for combined-arms support and logistical sustainment beyond the first few days. Instead, the conduct of Russia’s invasion indicates a half-cocked effort to make Ukraine flinch, the culmination of a failed strategy of coercion, rather than a calculated plan for conquest.
In February I said that it looked like a bluff to me, so I was certainly surprised when the invasion actually happened. But US intelligence, which seems to have been nearly perfect in those days, reported that Putin had ordered the invasion weeks before, and various Putin regime figures and surrogates had been predicting the invasion since November. Maybe there was a concerted program of mixed messages to make the threat real while keeping options open. But the result, from the Russian perspective, probably shows that more people within the military should have known more about the plan much earlier on.