President George W. Bush says he has no doubts about having waged the unpopular war in Iraq despite the "high cost in lives and treasure." He says to retreat now would embolden Iran and provide al-Qaida with money for weapons of mass destruction to attack the United States. Bush is to mark the fifth anniversary of the US-led invasion of Iraq on Wednesday with a speech at the Pentagon. Excerpts of his address were released Tuesday night at the White House. At least 3,990 members of the US military have died since the beginning of the war in 2003. It has cost taxpayers about $500 billion so far and estimates of the eventual tab run far higher. The president says successes in Iraq are undeniable, yet some in Washington still call for retreat. He says war critics can no longer credibly argue that the United States is losing in Iraq, so they argue the war costs too much.