Cool thing for the U.S. is that others will take the risk of implementing UBI before we start to think about it seriously. Save yourself the worry and hand wringing because other people and other countries will be laboratory for UBI.
On the other hand, UBI is fairly market orientated. Here's some economy points, go forth and spend as you will while we stigmatize you for it is a damn sight more American than let's organize consumers into a massive state backed bloc and drive down costs.
Well on the other other hand, the stigma alone could make it politically infeasble and societally unacceptable. Ezra Klein made the point that even if someone figures out a workable and affordable UBI system, it will take a long time before people are willing to accept large swaths of people leeching off the government in something that isn't retirement.