Last February, Mexico's former president, Felipe Calderon, posted 22 tweets about Yoani Sanchez, the Cuban dissident blogger. Each tweet was more enthusiastic than the last. "Brave activist for freedom," Calderon called her.

Ten months earlier, Calderon had been in Havana, on an official trip, dining and smiling with Raul Castro. There was no mention of Yoani or any dissidents and, of course, no visit with them. On the recommendation of the Cuban government, the "activist for freedom" was ignored.

Enrique Pena Nieto, Mexico's current president, should have set a different example during his recent visit to Havana. He has, after all, styled himself as a bold reformer, as he boasted the week before last in Davos, showing off a plan that would allow private investment in Mexico's energy sector for the first time in half a century.