The Nicaraguan town of León has declared the U.S. Ambassador Robert Callahan persona non-grata, The Nica Times has reported.

The snub comes amid a tit-for-tat dispute between the U.S. Embassy and León, a colonial city in the northwestern part of the country. Nica Times editor Tim Rogers writes that earlier this week, the embassy failed to invite León Mayor Manuel Calderón to the unveiling of the newly constructed León-Ponoloya Highway, an important project that was funded by the Millennium Challenge Corporation (MCC).

That's the same MCC that had cut aid projects in Nicaragua over suspected irregularities in the Central American country's November 2008 municipal elections. Questions about rigging the vote in favor of the Sandinistas, which sparked months of street violence and intimidation, have been at the heart of a nationwide scandal that prompted international aid donors to freeze much needed assistance to the country.

Being declared non-grata might be an improvement for Callahan, considering the harassment he has faced. After publicly calling the municipal elections fraudulent, protesters chanted "Get out, get out" and attacked the U.S. Embassy with rocks and homemade explosives last October.

Mayor Calderón's beef with the United States goes even further back than that. Calderón couldn't get a U.S. visa last year because of his role as an army commander during the so-called "Red Christmas," a deadly Sandinista push to relocate indigenous people in 1981. He is among a handful of Sandinista army leaders who stand accused by Nicaragua's Permanent Commission on Human Rights of torturing and massacring hundreds of Miskito people suspected of collaborating with Contras on the Caribbean coast. Their differences run deeper still if you consider Callahan's past. Years before he was sworn in as ambassador to Nicaragua in July 2008, Callahan served as spokesman and speechwriter for then-Ambassador to Honduras John Negroponte at the time of the U.S.-backed Contra war against the first Sandinista government.

In Central America, it's surprising how much can change over time, and paradoxically, with many of the same actors in play, how little things actually do change.

March 31: Join a live online discussion with one of Brazil’s leading civic experts, AQ author Paulo Rogério, and technology experts including Editor-in-Chief of Wired.com Evan Hansen on how to extend digital inclusion to minorities across the hemisphere. Find out more.