Re: So where would they move it to?
US Transit visas effectively no longer exist, because you have to apply online, then personally visit a US consulate/embassy for an interview. Waiting time is around 1 to 2 months, costs at least $160.
If you qualify for ESTA then it's more or less ok, except that you run a high chance of missing your flight because their immigration is incredibly slow - at least partially because they don't have the concept of staying airside when "in transit".
I never connect in the USA for South America anymore. Direct flights or via Madrid.