Defense Secretary Donald Rumsfeld has convened the top U.S. military brass in Washington for a two-day conference to discuss progress in the war on terrorism, as well as other pressing defense issues. The gathering, called the Senior Leaders Conference, began today and runs through tomorrow at an undisclosed location in the national capital region, according to Pentagon officials. Attending the meeting are the combatant commanders from around the world, the service chiefs and the Pentagon's most senior civilians.