Democracy and UBI are long-term enemies

The exact mechanics of UBI (Universal Basic Income) can be sliced in many different ways, but the basic idea is that every citizen is given a basic level of income. The poverty rate is usually picked as the 'basic' level.

There are many different details and arguments about how this could be implemented, or funded. Further, there are arguments about the amazing benefits that would accrue to the population, how it would be a complete failure, or how it would mitigate an impending disaster of widespread unemployment due to automation.

I want to skip over all of that and talk about what I perceive to be a long-term problem. So, let's start with UBI being implemented and say it works roughly as intended by its proponents: it staves off an automation mass-layoff disaster and provides a stable income to a large fraction of the population. In other words, working largely as designed by the proponents of UBI to solve the problems of the future.

But what happens in the longer term?

In 2020, the poverty line for a single adult in the US was just over $12,000 per year (federalregister.gov). Let's keep the numbers simple and start with $1,000 per month per adult as what gets implemented. Again, let's say that an automation mass-layoff disaster struck and some significant fraction of the population now relies on UBI for bulk of their income. The income distribution slides down and bunches up at the poverty line. Fast forward a decade or two and let's say that 50% of the US adult population is dependent on UBI for +90% of their income. As defined above and as stated repeatedly in policy discussions, the UBI is meant to aim at the income level that gets people to "poverty" level income.

But the political landscape will begin to shift as an increasing percentage of the population has a larger part of their income coming from such a program.

In a successful UBI rollout, there's going to come a time when there will be pressure to increase the payments. As much as current arguments are being based on basic meaning poverty level income, if a plurality of the voting population makes the majority of its income based directly on this redistribution plan, how long does it take before an enterprising politician runs on a platform to either change the UBI into a not-so-basic income, or to re-define what level basic means?

Maybe the voting public can keep themselves disciplined for a while, but really, from a person whose only income is UBI, voting for an increase in the distribution is all gain with no downsides. At some point there will be a critical mass of voters who have calculated that they can vote for themselves a raise. Perhaps the system can even handle it at first, but where are the incentives to stop this process? The only group incentivized are those with high incomes getting taxed at ever higher rates. As a group they are wealthy, mobile, and have options to fight increases these increases or to relocate.

The fundamental tension that I worry about is the pressure from (an eventual) majority of the voting population that would benefit from voting for themselves to get a raise at the cost of the smaller number of voters who would bear the costs of this raise. This plays out one of a couple of ways. One, the high-income group relocates in large enough numbers to cause a substantial shortfall in UBI. Two, the high-income group fights for control of the government by fighting against democracy (at least the one-citizen one-vote) so they have (or maintain) disproportionate influence in the workings of the government. Three, the high-income group continues to create wealth at a rate that increases faster than the majority can vote themselves raises. Four, the tax rates drops incentive to produce on an increasing fraction of very high income workers, hollowing out the economy from the inside. Long term, I don't see how this game is played out where a majority can in principle vote for themselves raises at the expense of a minority and the long-term structure of society stay intact.