NATO expansion. Discrimination and abuse of Russians. More than enough.
One wonders if Putin thought Ukraine was a weak pushover when he went in, and if so that speaks terrible of his intel apparatus and/or fellow official's that should have already briefed him concerning every aspect of that theater before he made his final decision to go in. The adapting of Ukraines military under threat has been an amazing thing to witness over these past 4 years, but Russia's adapting to the battlefield has also been impressive in their learned or adapted responses.
Both sides are paying a heavy price learning the tactics and strategies of a new modern high tech/low tech battlefield, otherwise that has new weapons systems and tactics being deployed in both directions.
What's bad for everyone in the world however, is the education in war and war strategies that is taking place for which is being looked upon with eagle eyes by many, otherwise looking at tactics and strategies that are teaching other's about these very interesting thing's along with the new weapons systems and new strategies involved.
Now every nation is adapting and changing war strategies and weapons systems along with training, and this is because so many new developments and tactics are being studied courtesy of the on going war in Ukraine.
China is probably going to be the biggest studying nation of the war in Ukraine, and it's because China wants to be the biggest and baddest in the world someday, and it wants Taiwan back as well, so it is watching and learning all in hopes to protect and push its expansionism to whatever level it thinks that it needs to push it in order to be top dog in protecting the homeland and interest abroad.
The war in Ukraine could have been stopped by now, but I believe that nation's have lost their ability to be looked upon as respected top negotiators, and especially so when they are dealing with a complete inward cultural melt down caused by the tolerating of to much evil within the United so called Nation's that are grouped together in globalism that is trying not to recognize sovereign borders any longer.
Peacemaker nation's who hoped to be a bright light at the negotiating tables have become failures, and this is because nothing gets done due to infighting. There is the lack of respect and integrity involved in the negotiating process also, otherwise whenever nations attempt to give it a go at trying to deliever peace once again in the world.
Example - Biden and his administration used a "weapons arming" idea to help out Ukraine. Why ? Because it new that it had no negotiating cards to bring to a table in the form of getting respect by having a neutrality plan for peace that would be workable while having a back up plan just as well.
TRUMP on the other hand is trying to pick up the pieces in order to come at it again in hopes to convince the two sides to stop, but the rift between the UK, the leftist/wokies and Trump is undermining the possibilities before anything gets done sadly enough.
Nation's at war will probably have to work things out on their own it seems, because respect of persons is no where to be found anymore these days.
Send Tomahawk missiles to Ukraine.
For what ?... It's over for Ukraine at this point right (?)
Why ? Because if it takes Russia every last resource and manpower that it has in order to win this thing now, then Putin and Russia are probably willing to go for it at this point.
The nukes for tactical use is probably his back up plan if all else fails, so if one keeps stomping on the bears tail while it's trying to eat, then one might finally get the reaction they didn't think possible in that theater.
Just observations and opinions based upon what I watch on the news is all. I can be corrected anytime.