UBI seems less risky than a union because of a long history of anti-union action, hostility towards employees, and lack of mobility once one is bound to a union. UBI provides flexible minimum support and someone could transform their life from one place to another by being sure they could at least maintain a minimum standard of living.

If they won't let you have a union then the ubi they give you won't put you on a stronger footing. Ubi could help create a minimum standard of living, that's what that tool is for, but that's separate from getting negotiating power for workers. For that, they need to negotiate together.

See jedberg. We have systematically destroyed the concept of growing with a company for it's duration in the US. Without the concept of mutual company-employee loyalty then something needs to protect inter-company transition/bargaining power.

Labor unions don't have to be tied to a single employer, or even a single country.

Unions only protect you in one job. A UBI protects you in all jobs.

If ubi can cover your costs of living. But if corporate america and government have broken the labor movement, then why would they give you ubi that truly gives you autonomy from work?

The point is not autonomy. The point is that it keeps you alive, so that you know that if you leave your job, at least you'll still have health care and food, so you won't die by being jobless.

It sets a minimum bar.

Realistically you need both -- a UBI and a union. The UBI sets the minimum bar that all jobs must reach, the Union sets the livable bar for one particular workplace (or maybe a group of similar workplaces).

UBI and Unions serve different purposes. A UBI prevents modern slavery, a Union provides for a decent quality of life.

Because we in the US need to understand that it's not about just passively being given something. This is about a whole country making decisions that steward the actual people who make it, not entities with highly biased representation.