Rubio says America is the only place where “your future is not determined by where you were born”. This just ain’t true. France, Germany, Sweden, Canada, Finland, Norway and Denmark help people with teh socialist programs and what do you know, they actually really help!
And you don’t need to take my word for it either, the Economist—an outfit with right-wing views on economic matters, but that’s also international in its outlook and thus not blinded by the solipsism of the American right—has covered this in detail.
This one stat isn’t the be-all and end-all of mobility. One nice thing about the United States and social mobility is that compared to most European countries (but not Canada or Australia, or for that matter Sweden in Europe) it’s easier for foreigners to move here and make their way. Still, the facts are the facts. The ex ante level of inequality in the United States makes social mobility hard, and we’re not doing anything like the kinds of investments in child nutrition, early education, etc. that could make up for it ex post.