WASHINGTON (AP) -- With the American death toll above 2,000, President Bush said Saturday the war in Iraq has required "great sacrifice," but that progress is being made and the United States must remain steadfast.In his third speech on Iraq this week, Bush sought to shore up flagging support for a war that began March 20, 2003."The best way to honor the sacrifice of our fallen troops is to complete the mission and win the war on terror," the president said in his weekly radio address."We will train Iraqi security forces and help a newly elected government meet the needs of the Iraqi people. In doing so, we will lay the foundation of peace for our children and grandchildren."Public support for Bush's handling of Iraq is at its lowest point, 37 percent, roughly where it has been since early August, according to AP-Ipsos polling.'Saddened' by indictmentAfter a tense week, Bush is spending the weekend at Camp David, the presidential retreat in Maryland's Catoctin Mountains. Before leaving the White House on Friday, he paused to express support for I. Lewis Libby, who resigned Friday as the vice president's chief of staff after being indicted for perjury, obstruction of justice and making false statements charges in a two-year investigation of the leak of the name of a CIA operative."We're all saddened by today's news," Bush said, adding that the U.S. justice system assumes that the accused are innocent and entitled to due process and a fair trial.Libby was a driving force behind the administration's march to war against Iraq and helped assemble evidence -- later proven false -- asserting that Saddam Hussein possessed weapons of mass destruction, which became the rationale for the U.S.-led invasion.Referring to Libby by his nickname, the president said: "Scooter has worked tirelessly on behalf of the American people and sacrificed much in the service to this country."White House officials took comfort that Karl Rove, Bush's chief political adviser, escaped indictment on Friday. But the investigation into his role is continuing.Bush lauds constitution voteIn his radio address, Bush said Iraq had passed an important milestone with the certification of passage of its new constitution."Three years ago, when Saddam Hussein ruled with an iron grip, the prospect of Iraqis voting on a democratic constitution would have been unthinkable," he said."Now, the Iraqi people have shown that individual rights and rule by the people are universal principles, and that these principles can become the basis for free and decent governments throughout the Middle East."Bush said Iraqi voters had refused to surrender to intimidation and had risked their lives for liberty."Our security at home is directly linked to a Middle East that grows in freedom and peace. The success of the new Iraqi government is critical to winning the war on terror and protecting the American people. Ensuring that success will require more sacrifice, more time, and more resolve, and it will involve more risk for Iraqis and for American and coalition forces.""The progress we have made so far has involved great sacrifice. The greatest burden has fallen on our military families. We've lost some of our nation's finest men and women in the war on terror," the president said.At Camp David, Bush is considering whom he will nominate to the Supreme Court. Joining him at the retreat was Harriet Miers, the White House legal counsel who withdrew her candidacy for the high court Thursday in the face of withering criticism from conservatives.In accepting her withdrawal, Bush said Miers would resume her duties helping to review candidates for judicial openings.Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.