The problems in both Venezuela and Colombia are very complex ;
In Venezuela, is a socialist leader (Hugo Chavez), who rose through the ranks of the military from a working class mestizo background. He tried a military coup to install a government using the socialist principals of the legendary south american liberator Simon Bolivar. The coup failed, and he was jailed - only to be freed from prison a few months later and to transform himself and his cause into a political force. He was elected by an overwhelming majority - mainly by the mestizo working class and poor of Venezuela. This much angered the middle class and upper class residents of Caracas and other large cities, who sought to use their influence in the free media to attack Chavez. This culminated in the unsuccessful coup - backed by the CIA and Washington - whereby Chavez was removed by force from power. However popular opinion was so against this move (engineered by "agent provocateurs" in Washington) and Chavez was - for better or worse - restored to power. He continues his "bolivarian revolution" to this day - bringing the vast privately-owned oil-feilds of Venezuela under state control to finance the work. Much to the anger of the US - Venezuela's largest customer by far. Chavez enjoys popular support from the majority of his population, whilst middle / upper class Venezualans and south americans in general at home and abroad see him as a despotic dictator who seeks to rob them of their hard earned wealth. It should be added that a large proportion of these people are mostly of European bloodlines and appearance.
In Colombia, there has been endemic violence for many, many years. This is largely due to the fact that the terrain of a large part of the country is located in the foot of the Andean mountain range. Not only does this make it impossible for the government to control the scattered and independent population of this area, but it provides that population with the means by which to earn their money raising the only crop that is profitable ; cocaine - 70% of which is shipped to the USA - the rest mostly to Europe. For all the Hollywood tales / propaganda concerning Colombia, very very few people in Colombia are drug users. Then in 1998, a strong president came along who seemingly had the right credentials - Alvaro Uribe. He was based in Colombia (believe it or not the previous President was resident mostly in Spain - on the other side of the Atlantic) and he showed a strong stance against the socialist rebels F.A.R.C (Fuerzes Armada de la Republica de Colombia), due to his kidnapped father dying in a botched rescue attempt by the Colombian Army. It should be noted that Uribe has been noted as having strong ties to the para-military groups - who operate outside the juristiction of the government in Bogota and have commited some of the worst attrocities known in recent decades in the cause of ridding the country from the F.A.R.C. (the gorrotting of pregnant women, the decapitation of young boys - all for simply living in areas policied by the F.A.R.C). It should be noted that the F.A.R.C responded accordingly to these crimes - neither having the moral high-ground. Both "illegal" groups are heavily involved in, and rely heavily on the financing from the trafficking of cocaine.
The United States has long sought, unsurprisingly, to exert a stronger influence in South America - a continant rich in oil and minerals - perhaps only comparable in it's resources to that of the other continent that has suffered at the hands of western greed for too long, namely Africa. The US's interference in the politics of Latin America is both long and documented in the blood-stained annals of 20th century history (Cuba, Colombia, Venezula, Argentina, Nicaragua, Peru, Chile, Panama etc etc...). The most recents concerns of Washington have been related to the election of the Socialist government of Venezuela (exceedingly oil-rich) it's "Plan Colombia" (the war on the production of cocaine) and Bolivia - another large producer of cocaine who's president, Evo Morales is not only full-blooded native indian, but rejects the criminalisation of farming cocaine due to it being the only crop that people can survive on in his mountanous country (previously named "upper Peru" - renamed Bolivia after the liberator Simon Bolivar).
In 2007 - Uribe and Chavez had an unusual alliance to secure the release of captives held prisoner by the F.A.R.C (who see Chavez as an ally against the imperialism of the USA). Uribe agreed on the condition that Chavez did not have any contact with the military of Colombia (for fear of aiding a coup in Colombia - as he had undertaken himself in Venezuela). Chavez apparently broke this condition, and the deal was broken off. Chavez decided to continue negotiations with tthe F.A.R.C anyway, and successfully delivered four long-held captives, who were released in Venezuela (the border between Colombia and Venezuela is mostly in rough terrain and highly pourous - a reason for Uribe's accusations of Venezuelan support for the idealogically harmonious F.A.R.C). This release obviously greatly embaressed the government in Bogota, Colmbia who had (since the dissolution of the pact between Chavez and Uribe) started a high profile campaign against the F.A.R.C. involving street protests, diplomatic missions to the drug-binging cities of Europe and a documentary on BBC2 featuring Uribe - hosted by the bass player of innofensive brit-pop act Blur.
Very recently, the Army of Colombia announced to the world that they had managed to kill F.A.R.C's no.2 and spokes-person Alias Raul Reyes. This was seen as a great victory for the Colombian military - however it looks likely to have opened a can of worms. Firstly, the killing took place across the border in neighbouring Ecuador. Secondly, the Ecuadorian media has reported that the cross-border incursion was of up to 10 kilometres and there is strong eveidence of a massacre of Ecuadorian civilians - in some incidences having been shot in the back wearing their pyjamas - men, women and children.
It is important to rememeber President Bush's recent tour of South American capitals - apparently on a mission to agree greater trade links. Mr Chavez (not a fool by any means) retaliated with an "anti-Bush" tour of those same capitals a few days later.
Since the cross broder incursion by the Colimbian army, not only the government of Colombia had to apologise outright for their attack on foreign soil (something which their puppet masters in Washington would do well to take note of) but the attack has received strong condemnation from Ecuador (who have moved their forces to the border with Colombia and closed their embassy in Bogota), but also (perhaps unsurprisingly) from Venezuela (who have also closed thier embassy and moved their forces to the border with Colombia) as well as strong criticism from nearly every single Latin American state as well as (perhaps surprisingly) former colonist Spain.
The path that Colombia will now follow will be precarious. They are extremely isolated, and already have an internal conflict. The armed forces are mainly of a working class mestizo background who would all undoubtedly choose to not kill their south american brothers in favour of the Washington agenda - should the involvement of the USA be come too obvious. We should all watch with interest as to the reaction of the US government, and also the opinions of US allies worldwide. Perhaps now that the US have seen the resignation of latin america's largest opponent to US interferrence (namely Fidel Castro), they see an opportunity to also rid themselves of the problem that is Hugo Chavez. What seems to be missing from the eqaution is the centuries of maltreatement of the working classes and the poor of this area of the world - the misunderstanding of which could lead to one of the most tragic, unjust and unfair conflicts of recent years. It would not only certainly lead to the further tarnishing of the US abroad, as well as the inevitable fall of the Colombian governement, but also the blood-shed of perhaps hundreds of thousands of innocents.