US Secretary of State Condoleezza Rice has admitted the US has made thousands of tactical errors in Iraq, but said it was right to remove Saddam Hussein.
"This could have gone that way, or that could have gone this way," said Ms Rice, adding that the US-led invasion was "the right strategic decision".
Ms Rice's comments came after she delivered a major foreign policy speech in Blackburn during her tour of the UK.
Her visit has sparked anti-war protests in the north-western town.
"I know we've made tactical errors - thousands of them, I'm sure," Ms Rice said in a session of questions after her speech, organised by BBC Radio 4's Today programme and Chatham House international affairs institution.
"But when you look back in history, what will be judged is did you make the right strategic decisions," she said.
"I believe strongly that it was the right strategic decision, that Saddam (Hussein) had been a threat to the international community long enough," Ms Rice added.
During her speech Ms Rice touched on a number of key issues of US foreign policy, saying that:
- no-one should doubt America's commitment to justice and the rule of law
- the US had no desire "to be the world's jailer", and that Washington wanted "the terrorists that we capture to stand trial"
- the cause of advancing freedom was the greatest hope for peace today
- the use of force "is not what is on the agenda now" in the stand-off over Iran's nuclear programme - adding that President Bush "never takes any option off the table"
- the US and Britain should continue to have "extremely close" relations and be united in the fight against terrorism
The speech was delivered on the first day of Ms Rice's two-day visit to the north-west of England.
Some 150 people had gathered in Blackburn to protest against Ms Rice's presence.
Many shouted "Condoleezza Rice go home" as she entered a local school.
A planned visit to a mosque in the town was scrapped because of fears of protests in the building.
Ms Rice is the guest of the British Foreign Secretary, Jack Straw, who represents Blackburn in the House of Commons.
Ms Rice has now gone on to Liverpool.