McGrath, I don't understand the connection between US & Mexico, and UK and Ireland. Mexico was never a province (or colony) of the US. Large chunks of territory that were once Mexican are now part of the US. The descendants of the Mexicans who lived there, if they live where their ancestors did, are US citizens now. What connection does that have with folks from Oaxaca who happen to be residing in California but aren't US citizens? The US used to be a colony of the UK; if I happen to take up residence in Belfast, should I automatically be allowed to vote there? (Or would I be? I plead ignorance, but somehow I suspect the UK requires more than "present" to be eligible to vote.)

I also don't understand the point of bringing up social and cultural facts that have not been in force for 140 years as if they had some bearing on the current issue. One could as easily tell Dr. Johnson to STFU because various Brit kings were nasty to the Irish and Scots.