$800/month comes out to just short of 50% of total tax revenue. You need a lot more than massive savings on welfare programs to pull off a 50% cut in all government spending, local, state and federal.
Ok. I'm just looking at a chart showing the US Federal Budget. 10% on welfare. 25% on pensions. That brings us to 35% so we're still short. Still about 15% off. I believe that the US has lower taxes than many other nations so for a UBI to work that would have to change and would bring us closer to the mark. Reducing some of the 21% spent on defence would also help and the health care sector would be interesting. I think for it to work you go to a completely public system. That would be important to make that $800 figure work and it might also reduce some of the inefficiencies in the current system (US is spending much higher % of GDP than other OECD countries despite having less coverage for citizens).
I think there are lots of ways to adjust current spending and make it work. My personal idea would not fly with the American public though (reduce defence spending by 80% and raise taxes - especially for higher earners).
