By Daniela Desantis ASUNCION (Reuters) -The United States has accused former Paraguayan President Horacio Cartes of “significant corruption” and of obstructing a cross-border criminal investigation. “Former President Cartes obstructed a major international investigation into transnational crime in order to protect himself and his criminal associate from potential prosecution and political damage,” U.S. Secretary of State Antony Blinken said in a statement, without naming the associate. “These actions enabled and perpetuated Cartes’ recently documented involvement with foreign terrorist organiz…