I noted recently that two Mexican generals had been arrested by state authorities on suspicion of links to drug traffickers. Late last night, the government took a third general into custody, and the arrests might not stop there. According to the New York Times, “local news reports suggested that the corruption investigation was continuing and could net other key figures in the drug war…the accusations against the third general…include that he ignored a tip by American drug agents about an imminent airplane delivery of a drug cartel’s cocaine in December 2007.”

Alejandro Hope, a private security analyst and a former Mexican government intelligence official interviewed by the Times underscored a point I made earlier. “There has been worry that the more you use the military the more corruption there will be, so one purpose of this could be to send a message.” Says Robert Bonner, who has been unambiguous in his support of Mexican President Felipe Calderón, “This is what Mexico needs to do. It needs to identify the corrupt officials and put them behind bars. I am encouraged because they are not trying to sweep this under the rug.”

But there’s another, less noble, possibility that could be animating this week’s action. As the Times notes, “It remained unclear why the men were detained this week for acts that transpired a few years ago,” but one of the generals arrested “had recently appeared at a security forum put on by a nonprofit group with ties to the Institutional Revolutionary Party, whose candidate for president, Enrique Peña Nieto, is leading by a wide margin in polls ahead of the July 1 election. Mr. Peña Nieto said the generals had played no role in his campaign, though General Ángeles served in Washington in the early 1990s under a former ambassador, Jorge Montaño, who is the party’s foreign affairs adviser and has met with policy makers and analysts in recent weeks in Washington.”