At its heart, is “Brexit” really any more complicated than whether you are self-centred and introspective (leave*) versus you care about the world and the next generation (stay)?
There is only really one thing in this world worth really worrying about, and that’s Climate Change. Make no mistake: this really could destroy civilisation. Really. Unless it is either stopped or mitigated, all that other stuff - jobs, health, education, even wars - is just polishing a turd.
Fighting climate change needs increased international cooperation. It needs national governments being held accountable through international agreements and organisations. The Brexiters and Trumps of this world are happy to feed off everyone else’s misery to line their own pockets. They will hopefully be dead before the shit really hits the fan. Hopefully, so will I. Our children won’t.
Humanity has progressed greatly over the past few hundred years. Knowledge, healthcare and the potential for political influence has been opened up (in developed countries, at least) to the masses. Let’s not support individuals who hark back to mythical “glory” days in which only the established elite had anything. In former times, when America or Britain was perceived as “great”, this was always at the cost of the poor and minorities. It was about lording it over your (perceived) inferiors, both nationally and internationally. It was about the status and riches of ruling classes. It was about powerful people sending powerless people to die in their millions for pointless causes. It was about gaining superiority in the game of “us versus them”.
In the 21st Century, greatness must mean something different. It must be about the state of the lowest citizen, not the highest. There is no “them” - there is only “us”. Nations and countries are arbitrary boundaries, drawn up for bureaucratic and political reasons, with no actual basis. Race is a myth. People are people, the world over.
Unless we realise this, we are all doomed. When the wings fall off and the plane crashes from the sky, it doesn’t matter whether you’re in business class or economy.
* There will of course be some UK “winners” in the Brexit scenario, who will benefit from the removal of competition and/or want to be a bigger fish in a smaller pond. However, to think that Brexit serves the nation’s self-interest, you probably need to add “deluded” to the attribute list, as John Major makes clear.