"Removing Saddam Hussein from power was the right decision -- and this is a fight America can and must win," Bush said in remarks prepared for delivery at the Pentagon.

The president reviewed triumphs and tragedies in Iraq -- from 12 million Iraqis voting in free elections to the beheading of captives. He also admitted the war was more costly than originally thought, but chided critics for their wide-ranging cost estimates.

When last year's upswing in violence led to a surge in troops, Bush said his administration "knew that if we did not act, the violence that had been consuming Iraq would have worsened, spread, and could eventually have reached genocidal levels."

The challenge ahead, he said, "is to consolidate the gains we have made and seal the extremists' defeat."

"The battle in Iraq is noble, it is necessary, it is just," Bush said, and "it will end in victory."