It can only do so either through taxation, or by printing money, as the government is not a value-generation enterprise.
If UBI gets its funding by taxation, UBI can't work economically (not to say it wouldn't be "UBI"). Even if you tax all the rich people, it won't provide enough money for the program. Besides, you can't really tax the rich, the moment you declare an aggressive taxation regime on them, they fly their money out of the country (and possibly their businesses too, which would generate poverty). If the assumption is that it would tax "everyone but the poor" then it's not universal "income", it's just another "social program" paid by the middle class.
If UBI is funded by printing money, then it's a debt generation engine. The USA is already heavily indebted due to at least 100 years of irresponsible governments spending a lot more than what they made through taxes. UBI would only make matters worse, and could easily lead to a currency crash within at most a couple decades (which would wipe out retirement funds, savings, etc. therefore generating poverty and causing social unrest)