Better than the Internet.
If that program existed today, it would be called 'Operation Latin Pride' and it would be implement by the 'Department of Global Liberty Management'.Goverment PR people in the 50's apparently weren't good at coming up with names for things.
I still don't understand where that term comes from, seeing as how Mexico is generally an arid place with little precipitation. Are their backs sweaty or do they have other porous secretions resulting in a moistured back?
According to the USS Internets, the term is originally derived from the wetness that is obtained when crossing the Rio Grande into the states.
Maybe the back is still wet because they had a backpack on and the rest of them dried in the dumb Texan sun.