By Matthew Davis
BBC News, Washington
President George W Bush has called on Americans to be patient over Iraq, in a passionate and ideologically-charged speech.
This was a delivery from a US president seeking to step up the defence of his Iraq policy in the face of falling popularity and growing doubts over his strategy.
George Bush reminded Americans of the threat of terror
The White House suggested Mr Bush would go into "unprecedented detail" about the nature of the enemy and the strategy for defeating them, but the president offered few hard facts in the speech to a Washington-based think-tank.
Instead he went on the offensive against a "global campaign of fear" which he said was assuming the proportions of the Cold War of the late 20th Century.
Seeking to demonstrate just how high the stakes were in Iraq, Mr Bush framed the conflict as the major battlefield for Islamic militants seeking to enslave whole nations and "intimidate" the world.
Insurgents in Iraq were part of an emerging, global terror offensive and were seeking to claim a strategic country as "a haven for terror", the president said.
The speech comes at a time when Mr Bush has lost a great deal of personal popularity, and support for the Iraq mission from Americans.
US military deaths in Iraq are fast approaching the psychologically important total of 2,000.
The president's policy also faces a crucial test in Iraq's 15 October referendum on a constitution, which the US expects insurgents to try to derail.
Mr Bush's speech - which follows a number of high-profile speeches by senior administration figures - was clearly aimed at bolstering support for the mission ahead of this critical period.
More than 1,940 US military personnel have been killed in Iraq
In a reminder of the threat posed to Americans at home and the need for them to support the War on Terror, the president said at least 10 attempted attacks by al-Qaeda had been foiled since 9/11 - three of them on American soil.
He also said there had been other attempts by al-Qaeda to reconnoitre targets in the United States or get operatives into the country, all of which had been disrupted.
Mr Bush also took the unusual step of naming and responding in specific terms to al-Qaeda figureheads Osama Bin Laden and Abu Musab al-Zarqawi.
"Bin Laden has stated that the whole world is watching this war and the two adversaries. It is either victory and glory or misery and humiliation," Mr Bush said.
"The terrorists regard Iraq as the central front on their war against humanity and we must recognise Iraq as the central front on our war on terror."
The president rejected criticism that extremism had been strengthened by the US presence there, saying: "We were not in Iraq on September 11 2001, but al-Qaeda attacked us anyway."
Facts on the ground
Such comments are unlikely to satisfy critics of the president's decision to invade Iraq in the first place, and who say the invasion has given al-Qaeda a toe-hold in the country.
Nancy Pelosi, the top Democrat in the US House of Representatives, said the US had gone into Iraq on the basis of false premises and the president had "mismanaged" the aftermath.
"He is trying to justify his actions with a series of excuses that are not justifications for being there," Ms Pelosi said following the speech.
Mr Bush's address also came hours after a bipartisan rebuff to the White House when the Senate voted to set new limits on the interrogation of detainees in Iraq and elsewhere.
Some see the 90-9 vote as indicative of a new boldness among those from Mr Bush's Republican party to challenge the White House over war policy.
The administration would desperately like to see the passage of a new Iraqi constitution - and elections scheduled for December - reinforce a sense among Americans that progress is being made.
All the expectations, however, are of an upturn in violence as these democratic watersheds are reached.
The president says it is a dangerous illusion to think the United States should cut its losses in Iraq and leave.
Yet facts on the ground may be more important than words in the air if public support for the war is not to move past tipping point.