Obama Declassifying Latin American Documents

This article in The Nation criticizes Barack Obama for his political use of declassifying documents. In short, why didn't he declassify the Argentina documents a long time ago? This part struck me in particular:

Declassification diplomacy, as Obama has practiced it, has been an effective but cynical tactic. We’re left to wonder, for instance, how much longer the Grandmothers of the Plaza de Mayo’s declassification request would have languished if Obama’s trip hadn’t happened to fall on such an unfortunate date. “These are political decisions,” said Carlos Osorio, the senior analyst for the National Security Archive’s Argentina Documentation Project and an expert witness who’s been called to testify in human rights trials in Argentina. “They have to do with diplomatic gestures to a particular country.” Administration officials, he said, “are aware of Operation Condor. They’ve been educated about it.” But “what drives them isn’t a research perspective or a historical perspective, it’s looking for an answer to a political situation.”

What occurred to me was that for people, especially politicians, who haven't studied U.S.-Latin American relations in detail, it's a history lesson, an abstraction, rather than a pressing issue. I've blogged more times than I count about the continued relevance of Cold War dictatorships in the psyches of so many Latin Americans. That's not how Obama sees it.

The U.S. is being asked all the time to declassify documents, but are doing so very selectively. There is no reason at all for the Argentina documents to stay classified this long, so why didn't Obama do so earlier? Was he just waiting for the photo op? And if the photo op had never come about, would those documents remain classified?