Beating Argentina in Buenos Aires is tough for anyone, even Brazil. But I think Brazil can thank their coach for this hammering. Last Sunday, Parreira used a 4 striker formation as Brazil defeated Paraguay 4-1 at home. He stayed with that formation and to think that playing Argentina in their house with only 3 midfielders and 3 backs was a good idea, well, he was delusional and got what he deserved. Brazil supposedly controlled the 2nd half but I'd say that was only because Argentina had the game in the bag and didn't want to allow another "Liverpool miracle" comeback.
As for MLS teams playing in intercontinental cups, the MLS champions and runners-up are committed to play in the CONCACAF Champions Cup. I don't know if any have ever been invited to play in CONMEBOL tournaments but I think travel schedule and cost would be a major consideration. These tournaments usually fall in the middle of the MLS season, so imagine playing a league match somewhere in the US on Saturday, then traveling to South America for a midweek Wednesday game and then return to the US for another Saturday league match. In April, DC United played Mexican champion Pumas UNAM in the semifinals of the CONCACAF Champions Cup. The drew them 1-1 at home then later, traveled to Mexico for a mid week game and got waxed 5-0. That's tough.
Just a bit of history.
In 1998, DC United won the mythic “continental double”. They started by winning the CONCACAF Champions Cup by defeating Mexican champion CD Toluca. By winning the CONCACAF Champions Cup, DCU earned the right to play the South American champion, Brazilian side CR Vasco de Gama, in the Intercontinental Cup. They won that 2 legged series to become the “Champion of the Americas.” (although the "home" leg for Vasco de Gama was played in Lockhart Stadium in Ft. Lauderdale).
As for the winner of the Copa Libertadores playing in the UEFA Champions League, I think you need to recheck your sources. That competition is only open to European teams.
