UNITED NATIONS - Nicaraguan President Daniel Ortega accused the U.S. of imposing a worldwide dictatorship and defended the right of Iran and North Korea to pursue nuclear technology in a speech Tuesday before the U.N. General Assembly meeting. Ortega also angrily denounced President Bush for criticizing Cuban leader Fidel Castro during his speech earlier in the day. Ortega, who took office in January, said little had changed since he last addressed the world body as the Marxist leader of Nicaragua's Sandinista-run government two decades ago. "The presidents of the U.S. change. And they may come to office with the greatest...