U.S. Defense Secretary Donald H. Rumsfeld, on a surprise visit with the troops three days after the devastating attack on a U.S. military dining hall here, told soldiers he remained confident of defeating the insurgency and stabilizing Iraq, while noting that to some "it looks bleak." "There's no doubt in my mind, this is achievable," Rumsfeld, who flew here under tight security, told a couple of hundred 1st Brigade soldiers of the 25th Infantry Division at their commander's headquarters. He promised them that later in life they will look back and feel pride at having contributed to a mission of historic importance. Hoping to bring holiday cheer to the wounded soldiers and demonstrate compassion for the troops' sacrifices, Rumsfeld landed in pre-dawn darkness and immediately headed for a combat surgical hospital where many of the bombing victims were treated after Tuesday's lunchtime attack on a mess tent. The most seriously wounded already have been transferred to a U.S. military hospital in Germany.