I also had a Washington Post link on this where President Uribe of Colombia personally accused Hugo Chavez of ordering the Venezuelan military to aid the FARC guerrillas, but it went poof for some reason and is no longer working.
Anyway, there hasn't been a full-fledged international war in South America since the Falklands, and that was twenty-plus years ago. Any thoughts on what might happen if this escalates beyond shouting? (Other than the USA almost certainly taking Uribe's side as their political position.)
It's no secret that Washington wants Chavez out of power. They stood by and watched (aided, some say) the semi-coup a while back with glee, until it all went rather pear-shaped. For sure, Uribe is their man in Bogota, they wouldn't abandon him for some commie wingnut like Chavez.
Like others have said I don't see how Mexico can have a case. It's not illegal for the US to put soldiers on their border. Also Mexico while wanting to make the US look bad they are in a pretty precarious position here.