Well, Argentina and Uruguay have enormous Italian settlements. Certainly more than half of the Argentinians and Uruguayans have Italian ancestors. The Spanish spoken in both countries has a little Italian accent.
During the 1990 World Cup in Italy, there were some racist sheets against Argentina (the Argentinians had beaten and eliminated the locals by a combination of luck and genius): "Argentini, razza di merda", it said ("sh*t race").
An Italian newspaper, very elegantly, put the last names of the Argentinian team players: "These are the last names of the so-called 'razza di merda': Pumpido, Giusti, Trebbiano, Ruggieri, Cucciufo, Battista, Maradona, Valdano". 8 out of 11 players had Italian last names. The racists were spitting to the sky.
Hey, I´ve to complain: Pumpido, the goalkeeper, is not italian but from Galicia, in Spain. I remember that match by the tv, was like a thriller, and looking at Maradona´s lips when the italians insulted to argentine hymn before the beginning of the match...ha! I wasn´t bored. BTW, many of those argentine players, italian origins or not, were playing in italians clubs, and Italia won the world cup of 1938 with many italians born in southamerica. Italians know who are argentines, but football is football, as Boskov´d say, this is: the most important of all. In a football match, players are insulting each others about race, religion, the mothers and the wifes, and other ugly words, but after the match all is forgotten. It´s true that many ultra-right groups seek in football clubs a place for meeting themselves and making propaganda, but this is not football. Argentines are sinners too, and in some kind they have, or had?, a feeling of superiority over others southamericans countries.
And about describing the race in documents, well, this is characteristic of USA. USA has many good things, but has a lot of bad things, and racial questions is one of them. In SouthAmerica is true that being white can make your life a bit more easy, but not in the sense of USA. The most important in SAmerica is being rich, but really in SouthAmerica aren´t hard prejudices about getting married with people of others races, and every year southamericans are more mixed and it´s not a problem, but the contrary.