East.Whether speaking from an intimate, dignified setting in the White House or before a symbolic, photogenic backdrop provided by uniformed troops, Bush has sought to use his addresses to the nation to mark key moments. On the deck of the returning aircraft carrier Abraham Lincoln, for example, barely six weeks after U.S. troops first crossed into Iraq, he declared an end to major combat operations after Saddam Hussein was overthrown. But he has also used them to try to mobilize support, pressure Congress and sway the views of a public that has gone from supportive to wavering to opposed to the war.On a Sunday night six days before Christmas in 2005, with the war nearing the end of its second year and support sagging, Bush, speaking from the Oval Office, called for patience -- and acknowledged that his decision to launch the war was based in part on faulty intelligence about whether Iraq had weapons of mass destruction. It was a major concession on Bush's part, and he coupled it with a declaration that the United States was on the road to victory, saying, "Not only can we win the war in Iraq, we are winning the war in Iraq."Speaking from the White House library Jan. 10, Bush presented his argument that averting defeat in Iraq required at least 20,000 additional troops -- the number turned out to be closer to 30,000 when support troops were added -- as he acknowledged for the first time that his previous strategy had failed.He did not say how long the troop increase would last, but military strategists said at the time that anything shorter than 18 months would probably be ineffective.Petraeus' testimony to Congress this week echoed those assessments. The general indicated it would be next summer before the troop levels could be brought back to 130,000 -- prompting critics to point out that one year from now, the troop levels will be just where they were a year ago.Since 2003, the president has woven a theme into his speeches; that Iraq is the "central front" in what he calls the war on terror -- a designation that some intelligence experts and political opponents say belongs to Afghanistan and Pakistan, where Taliban and Al Qaeda forces are rebuilding. And he has frequently delivered warnings that terrorists must be defeated in Iraq "before they can attack us at home." The timing of tonight's speech, two days after the nation marked the sixth anniversary of the Sept. 11 attacks, provides Bush one more opportunity to make that connection as he seeks to create another turning point in the political debate about the war.