It is not the liberal left that is the problem. It is the far right xenophobia, coupled with neoliberalism and climate skeptism that are ruining the world as we know it.
You could not be more wrong there used to be a dichotomy between the left and the right but now the political divide is between the authoritarians and the libertarians and some of the worst authoritarians are in fact the so called progressives who have thus far dominated the social media and who have been more than ready to dogpile any one who challenges their ideas or who refuses to endorse their orthodoxies. The reason that Trump is likely to win the US election is that the very people the authoritarian progressives have tries to silence are rising up and saying that they will not be ignored any more. The mane calling and attempts to shame people by calling dissenter xenophobes bigots or racists simply no longer works as populists like Milo are leading a a new surge of political engagement by people who have previously just looked the other way.
The progressive left have been trying for a generation to undermine the notion of the nation state and in the light of many wars between nations that had a certain logic to it but the problem comes form their rather loopy idea that all nations are equal in their social virtues and that all cultures are the same with maybe only some superficial differences. The cold hard light of political reality demonstrates that this is at best naive nonsense. There is simply no equivalence between a religiously motivated repressive totalitarian state and a mature secular western democracy. To denounce anyone who points this out as a “xenophobe” as progressives so often do is the height of stupidity. It also shows how weak “progressiveness” has become.
Finally we come to the issue of “climate change” which has largely been driven by the former communists who moved into environmental causes after the collapse of communism in the eighties, to them this cause is just another vehicle through which they hope to acquire global hegemony. and its a mechanism that many now pay lip service too but few really believe. Its also a mask for the real global problem of over population. But we are on the cusp of a rather radical solution to that which I expect to be some sort of global pandemic that will devastate the their third world in particular , I use to think it would be HIV/aids but now I think that it will be something more mundane that will piggy back on the growing resistance of Bactria to antibiotics, either way expect to see Africa, south east Asia the middle east and South America severely affected much more than the first world because well ordered societies will be better able to respond to such challenges than those which are corrupt and chaotic. The black death reduced some populations by 2/3 in the middle ages but we may see an even higher death toll because any modern pandemic will spread far quicker thanks to global air travel.
Any way I digress the point is that there is value in having the discrete entity called a nation where the people have more in common that they have that is different, the progressive idea of a borderless world has been a total disaster that has seen previously stable and cohesive societies import cohorts of people who have no desire to assimilate into the indigenous culture instead they have formed ghettos that give provide the breeding ground for nihilism and hatred for the host culture. Calling that out is simply entirely valid self defense rather than “xenophobia” and we will see more of it as the “progressives” are shown more and more to be in reality “regressive” and that their ideology is profoundly illiberal as a consequence.