On Saturday, legislators plan to swear in a new prime minister and Cabinet, completing a democratic transition that began in December with the election of its parliament. A main goal of the new government will be to restore security in Iraq, where sectarian violence and attacks by insurgents and militias have killed many people and led thousands of Iraqi families to flee their homes. The Bush administration hopes that full-scale democracy can unite Iraq's complex mix of Shiites, Sunni Arabs and Kurds, reduce public support for insurgent groups and militias, and make it possible to begin withdrawing U.S. troops sometime this year. In a speech in Baghdad on Thursday night, U.S. Ambassador Zalmay Khalilzad praised Iraq's outgoing prime minister, Ibrahim al-Jaafari, and said the inauguration will be a "historic step in Iraq's transition from dictatorship to democracy."