President Bush met with Ambassador Khalilzad alongside Secretary of State Condoleezza Rice and National Security Advisor Stephen Hadley.
They reviewed what the president called a realistic report from the ambassador about the challenges facing Prime Minister Nouri al-Maliki's government.
"On the one hand, he said they got a good government - goal-oriented people working to achieve certain objectives," said Mr. Bush. "And I know that you have been impressed by Prime Minister Maliki's determination to succeed and his willingness to lay out a common-sense agenda and then hold people to account. Zal also said it is still a dangerous place because there are people there who will do anything to stop the progress of this new government. You have to ask yourself, who's afraid of democracy?"
The president said he is concerned about foreign influences in Iraq, especially those in the neighborhood who he said might want to derail the progress of a free government.
Mr. Bush did not name names, but U.S. officials have expressed concerns about Syrian and Iranian influence in Iraq, where more than 130,000 U.S. troops still provide most of the security.
The president said, when America gives its word, it keeps its word, and American troops will help defend the Iraqi people, until the new government there is more capable of defending itself.
Khalilzad said U.S. officials are working hard to make sure that the new government in Iraq succeeds, because success there, he says, will solve problems elsewhere.
"Iraq is the defining challenge of our time," he said. "And what happens in Iraq will shape the future of the Middle East. And the future of the Middle East will shape the future of the world."
The president says they discussed the need to train more Iraqi police.
Neither of the men took questions nor spoke publicly about a former U.S. soldier in Iraq who is now facing charges of murder for the alleged rape and killing of an Iraqi girl.
Prime Minister Maliki Thursday repeated calls for an independent inquiry into the allegations, which include accusations that the Army private also killed three of the girl's family members before raping and killing her in their home south of Baghdad.
A written statement from the U.S. military command in Iraq said the alleged events of that day are absolutely inexcusable and unnacceptable. It said military investigators will fully pursue all the facts in a vigorous and open process.