The United States has called on Nicaraguans not to vote for the former leftist leader, Daniel Ortega, in November's presidential elections.
Mr Ortega ran for office in 2002 but was defeated
A state department spokesman said politicians like the Sandinista leader were "discredited figures from the country's political past".
Mr Ortega's Sandinistas led Nicaragua in the 1980s with strong US opposition.
The US controversially helped to arm and train the Contra rebels in their war to overthrow the Sandinistas.
After nearly 10 years of civil war, Mr Ortega lost the 1990 elections to Violeta Chamorro.
In 2002, he ran for office again, but was defeated by the current President, Enrique Bolanos.
Mr Ortega's Sandinistas later joined forces with members of Mr Bolanos' Liberal party who were angered by the government's decision to prosecute former President Arnoldo Aleman.
The ensuing power struggle between Mr Bolanos and his opponents led last year to international warnings that Nicaraguan democracy was under threat.
In October 2005, after months of wrangling, Mr Bolanos and Mr Ortega reached a deal to delay constitutional reforms which weaken the president's powers until after the elections.
The Bush administration has in the past accused the Sandinista leader and Mr Aleman of mounting a "creeping coup" against the Nicaraguan government.
On Monday, the US ambassador in Managua, Paul Trivelli, held talks with the country's main right-wing parties to discuss the possibility of their forming an alliance to oppose Mr Ortega.
But correspondents say the US policy could backfire and boost support for the Sandinistas.