At first the aim was to overthrow the Western-oriented government and install a puppet government in Ukraine. Then he realized Ukrainians didn't actually want that and were willing and able to fight back. So now he's basically looking for anything he can reasonably sell as a success to his own populace to be able to end the war as soon as possible. Annexing more of Ukraine, especially the Donbass, is one such thing. The problem is that Ukraine isn't just going to roll with that, plus sanctions will only increase, again leading to further economic decline. He really can't win anymore. Only face-saving options are becoming a second Iran / North Korea, or a Chinese vassal.

He wants the natural resources of Ukraine, and he wants to reimpose the Russian Empire, whose border encompassed a larger area than that of the Soviets.

Some sort of a stalemate which he can reasonably spin as a win.

If not, he will be killed.

Now its a life and death situation for him.

There isn't really a "concession" you could give that would make Putin happy.

Whatever you give Putin, he will want more. You could give them all of Ukraine, and Putin would start plotting his next invasion on whatever country he wants next (Moldova, Latvia, Poland, Georgia, etc)

Ultimately, He wants the "right" to expand and grow the his new Russian Empire to at least the size of the old Russian Empire or the USSR without the US or the EU or NATO interfering and getting in his way.

I partly understand where they're coming from with the 'evil west' moving right into their back yard. The US got pretty upset when the shoe was on the other foot in the Cuban Missile Crisis. But this is all way to out of hand now, it should have been sorted diplomatically, there's no obvious route to de-escalation that anyone finds acceptable.

Well... it's complicated by the firehose of Russian propaganda, but their actions make it clear: eradication and assimilation of Ukrainian culture and nation, and the seizure of Ukraine's territory and resources - 'genocide' sums it up succinctly.

Putin's regime has demonstrated that the lives of ordinary Russians are meaningless in the pursuit of its political goals - just like every Russian/Soviet regime before it. This implies that the war can only end with a total defeat for Russia or Ukraine.

Ukraine is in an existential fight, while Russia is in a political one. Disregard what anyone claims about corruption in Ukraine: its decentralized democracy has enabled it to survive so far, while Russia is (literally and metaphorically) disintegrating.

Russia is bigger with limitless brutality; Ukraine is determined and smart. We'll have to see which of these qualities brings victory...

Wendover Productions "Why Russia Is Invading Ukraine" on YouTube provides some good info. Some reasons include: - They need to secure energy sources (natural gas) to ensure a future for their economy. Ukraine was threatening this business by beginning to get funding from Western companies to develop their natural gas industry - Geographically, losing Ukraine to NATO/the West would result in compromised defensive lines - Putin wants to reestablish the former united Soviet Union

Whole Europe annexed is surely enough.

I assume that the guarantee that Ukraine will begin to respect the Minsk treaty that they signed.

Putin wants to secure Crimea, which is where a large part of the Russian navy is and their only connection to the Mediterranean.