Even a victorious war is destructive. I'd like to do without, but I am just a random hobbit in this regard.
It's a very extreme case, but it would get extremely messy. Putin on his own is something Europe should easily be able to handle as long as they've got Ukraine on their side. Trump's erratic disruptive attacks will hopefully end at some point. I'm not worried about Iran at all, except internally.
Seen the news of the past hours about the 2028 intention?
500+ million people and corresponding economy needs Ukraine to protect themselves? this is just plain pathetic or what's worse proof that the EU would fight Russia to the last Ukrainian
Those zany kids!
Putin cannot play the part Wilhelm played in 1914 because Russia has very little power.
Xi Ping cannot play the part Wilhelm played because he is too smart (he is one of the shrewdest and smartest leaders rn). If Xi Ping starts to lose it, then yeah, we may have WW1. Until then this is a very different situation.
Iran has a strong stance to significantly increase influence in the Middle East if not restrained: they have many way (not just Hormuz) to project power on oil countries, and essentially force them to switch sides.
My read on the situation is that Putin knows that he's stuck, and baiting nato into some (likely tepid) response gives him an excuse to expand the next call up / draft.
FWIW, as one potential size metric: casualties in Ukraine (so far) are comparable to the Korean or Vietnam War, and an order of magnitude less than the World Wars (even though the world has roughly 4x the population now than in 1939). It's much more comparable to those conflicts than either of the World Wars.
I believe it's also the case that more Vietnamese died during the Vietnam War than the UK/US/France combined during WWII as well.