"I'm so optimistic about the future, because I believe deep in everybody's soul is the desire to live in a free world," Mr. Bush said.
But a new report out from the CIA is not so optimistic, according to CBS News Correspondent Bill Plante.
It warns in part of a bleaker future for Iraq. The war-torn country could provide a haven for recruiting and training terrorists, according the CIA's sweeping study, which examines the challenges for the United States in the world over the next 15 years. The most worrisome trend, Plante reports, is an anticipated intensification in terrorists' ability to possess biological and nuclear weapons.
A former CIA agent told CBS Evening News that Iraq is now terrorism central.
"It's a magnet for Mujahideen from around the world — from all over the Arab world and all over the Muslim world, Indonesia and the Philippines," former agent Michael Scheuer said. "Fighters will be coming there to kill Americans."
In other developments:
The bus attack was the latest in a growing number of assaults on Iraqi security forces as the country prepares for balloting. Iraqis will choose a 275-member legislature in the first election since the collapse of Saddam's regime in April 2003.
The Bush administration hopes the election will be a major step in the building of a democracy and set the stage for the withdrawal of American and international military forces.
Before the war, the CIA found little evidence of al Qaeda ties to Iraq, but that has greatly changed, according to Scheuer, the former CIA agent and the CIA's new report.
The report comes at the end of a violent week, in which it was learned that the search for weapons of mass destruction in Iraq is officially over.
Although Iraq's long-suppressed Shiite Muslim majority is expected to vote in huge numbers, Sunni Arab clerics are urging a boycott and Sunni insurgents threaten attacks to disrupt voting, fearing the loss of power to Shiites.
Despite the threats, U.S. and other foreign troops plan to stay in the background during the balloting, turning over primary security responsibility to Iraqi forces, which have been criticized for poor performance and training.
Brig. Gen. Jeffery Hammond, deputy commander of the 1st Cavalry Division, said violence could keep some Baghdad residents away from the polls.
He warned of a further surge in bombings and other violence as the election draws near and said there was no guarantee Iraqi and American forces could stop a spectacular attack causing mass casualties.
"If I told you I could guarantee that, then I'd be a fool," Hammond told reporters Friday.
In Mauritius, U.N. Secretary-General Kofi Annan said conditions for elections in Iraq were "far from ideal." He said participation by Sunni Arabs was critical to ensure the new government is truly representative and urged Iraq's interim government to "intensity its effort" to draw in Sunnis.
Attackers in Iraq's north killed three officials of a party representing Iraqi Kurds, who also are working aggressively for a high turnout in the election, which is expected to pry power from Iraq's long-dominant Sunni minority.
Gunmen also killed an Iraqi election official in western Baghdad late Thursday, police said, marking at least the seventh such killing ahead of the vote. Attackers in a passing car shot Abdul Karim Jassem Al-Ubeidi as he headed home, police said.
Sunni militants claimed on Friday that they were behind Wednesday's assassination of a Shiite community leader who had promoted the election on behalf of Iraq's top Shiite cleric, Grand Ayatollah Ali al-Sistani. Ansar al-Islam said it killed Sheik Mahmoud Finjan because he was a "big supporter of the elections."
"We ... call upon all brother citizens not to participate in the elections because we are going to attack voting centers," Ansar al-Islam said in a statement posted on a Web site used by insurgents.
In Baghdad late Friday, insurgents fired two rockets near the Sadeer Hotel, which is used by Western contractors, and a third near the Ministry of Education, but caused no casualties. The blasts broke a lull of about two weeks in insurgent shelling of the city center.
Attackers fired a rocket-propelled grenade at an Iraqi police patrol in the Amiriyah district on the western edge of Baghdad. Three explosions also were heard near the main road from central Baghdad to the city's international airport, police said.