What? In other words, you're saying: "Russia is losing war with Ukraine, so it wants to start a second front with bigger enemy".
Also, how's Ukraine war is sustainable for Ukraine? It's economy is non-existent (almost 100% dependent on western donations), it has less than 50% of population of 2022 (they don't publish any population stats directly, but if you combine available statistics, there are about 10-15 millions left most of them old retired people or young people that are too young to send them to the front lines), they are losing territory every day.
This is some weird "Ukraine is winning but front is moving in the wrong direction" logic.
Not all wars have a simple way to say who is winning, who is loosing. See the Vietnam war, different Afgan wars.
I think you’re misreading the comment and conflating Putin’s survival with the current war. I believe the OP is saying the administration can’t keep selling the war with Ukraine as a good idea indefinitely and will need to pivot to something more marketable. In our Internet-shaped world, everything is entertainment. This particular show has run its course and needs a pivot, add new actors, make a Very Special Episode or kill off one of the main characters.
Ukraine is gaining some ground, but very slowly. It's basically a stalemate. Except that Ukraine is making the war extremely costly for Russia with the recent attacks on refineries and other targets deep into Russia.
As long as the EU keeps supporting them, I think Ukraine will be better able to maintain the current situation than Russia. But Ukraine is nearly as exhausted as Russia, and I think a European coalition sending real practical ground and air support would help a lot. I suspect sufficient support could force a breakthrough in southern Ukraine an liberate a very large chunk of land very quickly.
The reason that's not happening is either that NATO thinks this would give Putin the excuse he needs for large scale mobilisation, or simply because Europe is afraid to get its hands dirty. I don't think the former is nearly as big an issue as some believe; Putin has never needed any action from NATO or EU members to justify escalation, and has never responded to imagined red lines getting crossed.
The latter is more likely. I think Europe needs to remember the sacrifice that Canada and the US brought to liberate Europe in WW2, and recognise the moral obligation that creates to liberate others in a similar position. Like Ukraine today.
A war doesn’t need to be sustainable for Ukraine, it’s existential. For the aggressor that backstop doesn’t exist. They could literally stop the war anytime they wanted so they need to continue to prove it’s sustainable to keep doing it.