Not to defend Putin, but I think people are seriously underestimating the historic and diplomatic burden of the situation. Here are some important key factors that have provoked Russia's encroachment:
1) NATO Eastward Expansion
Russia has been very skeptical of NATO's progressive eastward expansion. The first one happened in 1999, when Poland, the Czech Republic and Hungary joined the NATO. In 2004, the Baltic states followed and while the Sovjets made it clear that they did not approve of this, none of these states were close to their borders. Russia was willing to live with it until the Bukarest summit, when NATO annexed the Ukraine. In 2008, Russia considered this a direct threat to their sovereignty. The NATO Eastward Expansion as driven forward by the West in a very foolish, hasty and callous way.
2) Ukraine's ethnic composition
As we can see, East Ukraine is predominantly Russian. From a Russian point of view it could be argued that they are merely seeking to repatriate their population, which is heavily promoted by the recently formed sovereign republics of Donetsk and Luhansk. In a sense, the Russians might feel about this like West-Germany reannexing the East-Germany. Now the West claims that the Donbas referendum was faulty, but Russia recognized its legitimacy for obvious reasons.
3) Rising anti-EU sentiment
The Ukraine is a
deeply divided country, between the pro-European west and the pro-Russian east. I mena, just look at these surveys:
A majority of Eastern Ukrainians neither want to join the EU, nor do they wish for their country to join the NATO. Ukraine's political regime and the West did almost nothing to attenuate that situation over the last decade and this is what ultimately happens if you let theses divisions fester and grow.
4) Europe's dependence on Russian gas
Germany in particular has been warned about its precarious dependence on Russian gas and how it might embolden the eastern bloc. Not much was done about it though and halting Nord Stream 2 is only spurring Putin on. The reaction is certainly understandable, Germany wants to show a strong hand, but it might end up only in marking the point of no return for Russia.
5) No strong European leaders
Seriously, who do we Europeans have to negotiate with Putin? Scholz? Marcon? Frikkin' Ursula von der Leyen? None of them are adapted to the Hobbesian worldview that represents Russia's foreign policy and Putin's leviathanic political hegemony.
It's a truly horrible and f*cked up situation.
Not long ago I came across this European peace clock:
It was reading 76 years, 1 month 1 day and 18 hours. It saddens me greatly that we might have to reset it now