Mark Weisbrot is co-director of the Center for Economic and Policy Research, in Washington, D.C.

Last Thursday the United States expelled the Ambassador from Ecuador, in retaliation for Wednesday's expulsion of the US Ambassador from Ecuador. This now leaves the United States without ambassadorial relations in three South American countries – Bolivia and Venezuela being the other two – thus surpassing the Bush Administration in its diplomatic problems in the region.

US Ambassador Heather Hodges was declared "persona non grata" and asked to leave Ecuador "as soon as possible," after a diplomatic cable released by Wikileaks showed her saying some disparaging things about Ecuador's president, Rafael Correa. In the cable she alleges that President Correa had knowledge of corruption by a former head of the national police.

Although the Bush Administration intervened in the internal affairs of countries such as Bolivia and even Brazil, it was somewhat better at keeping its "eyes on the prize," and avoiding fights that would distract from its main goal. The prize, of course, is Venezuela – home to the largest oil reserves in the world, estimated by the US Geological Survey at 500 billion barrels. Washington's goal there for the last decade has been regime change. The Bush team understood that the more they fought with other countries in the region, the less credible would be their public relations story that Venezuela was the problem.

It's nothing personal, really – Venezuelan President Hugo Chávez could have chosen to be the perfect diplomat and he would still be treated in much the same manner by the US government. And it's not the oil itself, since Venezuela still sells us more than a million barrels a day and there is a world market for oil in any case. It's just that any country with that much oil is going to have regional influence – and Washington just doesn't want to deal with someone who has regional influence and doesn't line up with its own goals for the region – not if it can get rid of them. And they have come close to getting rid of Chávez, in the 2002 coup – so they are not giving up.

But Washington is losing ground there too. A big blow was the change in Colombia's foreign policy last summer, when President Juan Manuel Santos took office. An important part of Washington's strategy in Venezuela is to maintain tension between Colombia and Venezuela. They have a head start on this project since the 2000 kilometer border between the two countries has been plagued by paramilitary and guerrilla violence for decades. Conflict between Venezuela and Colombia is also important to Washington's electoral strategy in Venezuela. When there is trouble between the two countries, as in 2009, when Venezuela cut off bilateral trade in response to the US effort to expand its military presence in Colombia, it has a negative impact on a lot of Venezuelans in border states. This helps garner some anti-Chávez votes in border states, as in last year's congressional election in Venezuela. And accusations of Venezuelan support for the FARC guerrillas in Colombia – despite Washington's failure to offer any evidence – are a key element of bringing its anti-Venezuela efforts under the "war on terror" umbrella.

Although Colombia's previous president álvaro Uribe was – in recent years – very much allied with the United States' strategy toward Venezuela, Santos immediately rejected it and decided to make peace with Chávez. This turned out to be quite easy to do, despite their past fights when Santos was Uribe's defense minister. As anyone who follows Venezuela knows, Chávez is friendly to any head of state or government that is friendly to Venezuela.

Santos' U-turn towards Venezuela is very interesting for several reasons. First, it shows how important regional economic integration is as a force for peace and stability in the area. The attempt by Washington and Santos' predecessor to expand the US military presence in Colombia led to a cut off of $2.3 billion dollars of Colombia's exports to what had recently become their second most important trading partner, Venezuela. This was more than 11 percent of Colombia's exports, and the bulk of it was in livestock and textile products for which replacement markets were not so readily available. Venezuela also has very close relations with Brazil and most of the rest of South America, and they all felt the same way about Colombia's foreign policy. They were especially concerned about the US military expansion in Colombia – and even more opposed after US Air Force documents made it clear that this expansion was for "mobility operations … on the South American continent" and against the "constant threat" from "anti-US governments."