Defense Secretary Donald H. Rumsfeld returned to Washington Sunday after his surprise trip to Iraq. Rumsfeld's press secretary, Eric Ruff, said the defense secretary did not meet with any Iraqi government officials - as has been his usual practice - before leaving the country around noon Sunday. ``It was not a public trip whatsoever,'' Ruff said. The main purpose, he said, was to express thanks to the U.S. troops and their commanders. Rumsfeld met over dinner Saturday with several top commanders, including Gen. George Casey and Lt. Gen. Peter Chiarelli, the two most senior commanders in Iraq. He also met...