TAM and AA were once AAdvantage and code share partners. I think it may be right to say that no airlines that were AA partners ever even seriously considered joining oneworld after the initial experience with AA. At the time TAM left AAdvantage, the commentary in Rio was that AA had shown TAM the door because it didn’t want competition on the routes from Brazil to North America. In particular, TAM was starting up Rio – NY and AA didn’t want anyone at all flying that route, much less an AAdvantage partner, since AA was getting away with putting Rio passengers on its highly lucrative São Paulo route. We heard from friends that AA treated TAM as a very junior partner that didn’t know its proper place and was not sufficiently grateful for AA’s grant of AAdvantage membership. TAM also competes with BA from Brazil to London. It might be that LATAM simply isn’t wanted in oneworld. AA would probably prefer to set up direct AA flights from North American to the main cities in South America and not bother with connections to smaller places. BA may well have similar inclinations.