"I think that it is done in different places for different motivations," says Mr. Shifter, who testified before the US Congress last year on the implications of Venezuela's increased military spending. "[Mr.] Chávez is using this as part of mobilizing the country and thinking of a possible attack from the US. In Chile, it is much more about giving the armed forces what they want. Colombia spends because a lot of the [US] aid comes in the form of military equipment."
The problem, continues Shifter, is that "there is tremendous mistrust between countries ... if you don't know what your neighbors' intentions are, then it is natural is to build up as much as you can to prepare for any contingency."
Some South American nations worry about Chávez's ambitions and do not want him to gain a significant military edge.
"Brazil won't say it, but Chávez's build up is what has made it invest in its military," says Reserve Col. Geraldo Lesbat Cavagnari, coordinator of the Strategic Studies Group at Unicamp university in São Paulo.
Brazil and Venezuela already vie for political supremacy in South America with Chávez bringing together the radical leftists under his socialist banner and President Lula leading a more measured coalition of social democrats. At this point, the two leaders are friends and the two nations have no border quarrels or historical feuds that could flare up. But there are tensions between Venezuela and Colombia over gas-rich territorial waters and border areas where Colombia's FARC guerrillas are active. And Veneuzela has made claims on the western part of Guyana.
But few people believe Chávez is buying weapons in order to attack a neighbor. He has warned opponents of his Bolivian ally Evo Morales that "rifle and machine guns will thunder" if they try to topple President Morales but Venezuela still does not have a military machine capable of shock and awe, analysts said.
In addition, its army is one-third the size of Brazil's, and distinctly less experienced and battle hardened than neighboring Colombia's.