Thanks. That explains it better than anything else I have seen so far.
Is it safe to say that PRD would be the party we least want to win?
It depends on the perspective. If you were a conservative living in Mexico, you definitely would not want PRD to win. They're a bunch of demagogue socialists who believe in wealth redistribution and would govern like Hugo Chavez.
From the perspective of conservatives in America, PRD is the only major party in Mexico that DOESN'T believe in open borders. PAN and the crooks at PRI love open borders because of the money it brings home in Mexico. PRD views people fleeing their country as a national embarrassment and Castro-style socialists want to keep people from fleeing their country and will keep them there by force if necessary.