Putin saw an opportunity and went for it.
We've made mistakes in the past. Hitler in the '30s.
Now the West is weak again. The West is too focused on maintaining their generous welfare state so they've neglected to make weapons.
Fortunately, the Russians are too corrupt. So they've messed up. But by the time this is over, they may still take half of Ukraine. No reason for them to stop the war now. The West is having "Ukraine Fatigue"
Biden refuses to make deals with the Republicans to support Ukraine.
Biden would rather let Ukraine fall and blame it on the Republicans.
Putin made a poor calculation - period. However, he never lied about it. Western leaders lied and despite assurances given they kept pushing in the Ukraine.
However, people in the West seem incapable of seeing this from the Russian view, a nation defined in part by the bloody invasions of the past. It is ridiculous to you and I, but the Russian people always fear invasion from Europe. It’s a cultural thing - much like the Irish have a chip on their shoulder because of things that happened over 100 years ago or China has an ingrained hatred of Japan for offenses suffered generations ago.
Russia did not want NATO in the Ukraine. There is nothing about the Ukraine being in NATO that made the situation safer for anyone - nothing. Why it is okay for us to have a “Monroe Doctrine” but Russia, a nation actually invaded multiple times, cannot? Why did our state department climb in bed with Soros NGO’s in the Ukraine with people like Nuland in charge of “diplomacy”. Merkel admitted that Western leadership lied to Putin.
Furthermore, Ukraine had its own internal strife and corruption problems and they were not behaving well either.
I don’t like any of the “leaders” involved in this mess, but for the life of me I cannot figure out how/why any person in Ukraine, Russia, Europe, or the US is better off (or safer) because of this.
You might be right about Biden’s intent, but sadly we are all Americans and blood stains everything. The election of Biden had a price.