billion worth of intervention by a foreign power in a US election at the time, and proportionately five times the amount George Bush had spent on his own election campaign. When Violeta Chamorro visited the White House in November 1989, the US pledged to maintain the embargo against Nicaragua unless Violeta Chamorro won. There were reports of intimidation and violence during the election campaign by the contras, with a Canadian observer mission claiming that 42 people were killed by the contras in "election violence" in October 1989. Sandinistas were also accused of intimidation and violence during the election campaign. According to the Puebla Institute, by mid-December 1989, seven opposition leaders had been murdered, 12 had disappeared, 20 had been arrested, and 30 others assaulted. In late January 1990, the OAS observer team reported that “a convoy of troops attacked four truckloads of UNO sympathizers with bayonets and rifle butts, threatening to kill them." Years of conflict had left 50,000 casualties and $12 billion of damages in a society of 3.5 million people and an annual GNP of $2 billion. After the election, a survey was taken of voters: 75.6% agreed that if the Sandinistas had won, the war would never have ended. 91.8% of those who voted for the UNO agreed with this (William I Robinson, op cit). The Library of Congress Country Studies on Nicaragua states: Despite limited resources and poor organization, the UNO coalition under Violeta Chamorro directed a campaign centered around the failing economy and promises of peace. Many Nicaraguans expected the country's economic crisis to deepen and the Contra conflict to continue if the Sandinistas remained in power. Chamorro promised to end the unpopular military draft, bring about democratic reconciliation, and promote economic growth. In the February 25, 1990, elections, Violeta Barrios de Chamorro carried 55 percent of the popular vote against Daniel Ortega's 41 percent. Opposition (1990–2006) In 1987, due to a stalemate with the Contras, the Esquipulas II treaty was brokered by Costa Rican President Óscar Arias Sánchez. The treaty's provisions included a call for a cease-fire, freedom of expression, and national elections. After the February 26, 1990 elections, the Sandinistas lost and peacefully passed power to the National Opposition Union (UNO), an alliance of 14 opposition parties ranging from the conservative business organization COSEP to Nicaraguan communists. UNO's candidate, Violeta Barrios de Chamorro, replaced Daniel Ortega as president of Nicaragua. Reasons for the