The Chinese would certainly just appoint a new president, no problem. Xi might be in charge, but the Chinese communist party isn't some vestigial organ. Russia, however... Putin's been exclusively in charge for long enough and with no immediately clear successor that I'm almost certain that his death is going to result in a power struggle and civil war.

You'd have power vacuums.

In America it's not too late. We have a clear succession strategy. It sucks...I think you'd have to pick people off till you got to Rubio to get back to something closer to normal. He's #4. If you don't stop there...it gets a lot worse before it gets any better.

China, Russia, and especially Best Korea are so deeply entrenched, I don't think succession would go as cleanly.

I know too little about Russia to know who is a contender to replace Putin or if when he goes the system that created him will go too. I am trying to educate myself on that.

As for China, I know a bit more but I am no expert. Given my limited insight, I am surprised that Xi is still in power. I expected the Communist Party to have 'neutralised' him, not necessarily bumped him off but to have taken away his power and reduced him to a figurehead, especially after he mishandled the pandemic and has struggled to fix China's economic woes. He is basically a thug. If all you have is a hammer, every problem is a nail. But you cannot beat a pandemic with a hammer nor fix inflation or unemployment or pollution with one. You must have as many tools as possible - Chinese perfected the toolkit of government over thousands of years. Sophisticated people in Chinese government must think Xi is an ignorant lout. I suspect they keep him in place because its better for the people who really run China to have a useful idiot as a puppet than to go through the uncertainties of replacing him - more or less how they handled the Kim regime in North Korea until lately. Putin and Kim collaborating on Ukraine must have really angered China which is probably why Chinese are considering sending 'peace-keeping' troops to Ukraine. Xi is a pig in a drawing room and the real government is just working around him.

It is hard to tell how much of the reportage about Xi is 'smoke and mirrors'. I recently saw a viral report on Reddit and in The Guardian newspaper (probably going around all the news outlets) about Chinese military exercises and some special navy vessels (biggest of their kind! etc) they had which were supposed to provide support for amphibian landings of tanks etc. Every report spins this as 'China war games is preparation for invading Taiwan - shock!'. I am very sceptical. Xi is apparently the driving force behind sabre-rattling rhetoric against Taiwan and building up PRC military might (his new bigger hammer), but I reckon most of Chinese government are not interested in a war with anyone least of all Taiwan - I think they expect to recover Taiwan eventually, by peaceful means, and are happy if it takes a century cos that long timescale is how Chinese think. So, given this split between Xi and the rest, I have the sense this whole media story is just a performance - whether it is to fool the world about China's military aggressiveness (advertising Xi's policy) or is some part of Chinese administration doing this to fool Xi he's still in charge (covert anti-Xi policy), I cannot tell. I just don't have enough facts to judge what these military manouvres tell us about Chinese government or, on the bigger scale, what real difference it would make if Xi was not around.

We (in UK) get 24/7 coverage of Trump's idiocies but not real information on other political leaders. I am European and I could not name five European political leaders, let alone predict the outcome if one were assassinated. As for politics in rest of globe, I am just clueless for the most part but I do try to educate myself. I have to create my own news feeds because the MSM is worthless.