The biggest problem, one where the trend is running in the wrong direction, is how to fund UBI. If we assume that labour will be increasingly replaced by capital in the future, then I think this ultimately comes down to the following question: how do we tax increasingly mobile capital? I'm reposting here, but it seems particularly relevant. Because of the relative (and increasing) mobility of capital, countries have incentive to undercut each others' taxes on capital, to attract that capital into their country. There seem to be two directions we can go in:
1) Give up on corporate tax and shift the tax burden on to less mobile bases (e.g. land, consumption). This scenario seems to be slowly playing out across the developed world. I'm not sure this could fund UBI, and does little to mitigate the negative effects of capital accumulating in fewer and fewer hands.
2) Engineer some kind of grand international agreement on corporate tax rates: a 'Bretton Woods areement for corporate tax', if you will. This would be necessary because there's such a strong incentive for countries to 'undercut' each others' corporate tax rates (to attract foreign capital investment, tax havens being the extreme example of this). Such an agreement would require: a specific agreement on minimum corporate/capital tax rates, the participation of countries representing the bulk of the world's production output, and provisions that levy punitive tariffs on non-complying, and non-participating, countries that go below the minimum rate.
I've long thought option 2 to be basically impossible. But I've begun to wonder about this. In a strange way, Trump's presidency might be the golden opportunity. He seems to be just the right amount of crazy to do it. I couldn't imagine an 'establishment' president going near something like this. And I think only the US could lead such a process, maybe with some quietly pre-agreed support from China. Given the capital flight China is currently plagued with, their precarious public finances and their main central banker publicly stating support for some kind of international agreement on capital controls (he explicitly invoked Bretton Woods), it seems like a few stars are aligning. I imagine the Chinese communist party is also acutely aware that if the music stops, their Bastille will get stormed.
It's a tricky proposition though. It would have to be 'sold' skillfully. Essentially, we would need to convince the (marginally) most powerful in society (government) that they are about to be eclipsed by another group (capital owners). Perhaps our 'automated future' is the narrative to go with. Something like: As labour is replaced with algos/robots, then by definition production becomes more capital intensive. So more and more of the gains from production and trade accrue to a fairly small group of capital owners.
It's conceivable that, in the not too distant future, some of these mega-corporations will have net incomes that rival that of even large, first-world governments. At this point, they will pose an existential threat to liberal democracy as they will have the means to overcome the will of the majority and even the most co-ordinated resistance (i.e. by employing a large 'private security force'). Not to mention the immense soft-power they will wield given they will control most of the world's means of production.
So, although this may all sound crazy, it would be unwise and dangerous to allow things to reach a stage where liberal democracy is imperilled by this concentration of wealth. Therefore, we must tax corporations/capital in a way that leaves them nowhere to run (i.e. via an enforced international agreement on rates). A fair chunk of this revenue should be redistributed to (former) workers in the form of basic income in the interest of public welfare and social stability.
It's good populist policy too, something that Trump seems well suited to selling (although he'll face significant opposition from those suckling on the corporate teat i.e. mostly everyone, including the 'mainstream' media).
Note: I'm not really keen on emotive arguments like the above, but I think some version of the above is what it would take to sell a radical proposal like an international agreement on corporate tax rates to sustainably fund basic income. Although not exactly a 'glorious revolution', it probably beats the hell out of living in a world that has become a giant company town.