You have to understand that this war threatens a fundamental pillar of russian society as a whole: [View all]
Russian society is based on several core pillars:
1. "Russian Exceptionalism": All countries are bad. All politicians are bad. Scientists, economic leaders, celebrities, whatever. Everybody is bad. There is no good in this world. No exceptions. .............................. Except Russia and russian politicians.
2. "Russia is fundamentally good": Russia is a bastion of peace, diplomacy and religious piety, besieged by a sinful, war-hungry world.
3. "The russian government is infallible": Sure things are bad, but who are you to criticize the government? They have access to way more information about what's going on. They know what they are doing. How can you be so arrogant? You should be ashamed of yourself to speak out without knowing what you are talking about.
4. "The West wants to destroy us": The West wants to break Russia apart into smaller countries, just like they broke the Soviet Union apart.
The war threatens the third pillar. The authoritarian society of Russia is based on the premise that you can trust the government to be infallible.
Imagine the pure innocence of belief. A unity of purpose, united in one credo.
And then imagine that ugly gnawing feeling in the back of your head when you realize that the government is making mistakes, BIG MISTAKES, and that belief that everything will be alright is being taken away from you.
And this feeling, of Russia no longer being united in this core belief, triggers another fear: A Russia where different political powers are fighting each other, as a predecessor to Russia breaking apart.
Putin must win this war, or else his government will be toppled by critics and backstabbers.