President George W Bush has compared Osama Bin Laden to Lenin and Hitler in a speech to US military officers.
"Underestimating the words of evil and ambitious men is a terrible mistake," he said as he quoted extensively from Bin Laden and other al-Qaeda figures.
He said the world had ignored the writings of Lenin and Hitler "and paid a terrible price" - adding the world must not to do the same with al-Qaeda.
Mr Bush has been defending his security strategy as mid-term elections loom.
His speech on Tuesday - the day following the US Labor Day holiday - coincided with the country's traditional start date for election campaigning.
"Bin Laden and his terrorist allies have made their intentions as clear as Lenin and Hitler before them," he said.
But, he added, the US and its allies could be confident of victory in "the great ideological struggle of the 21st Century" because "we have seen free nations defeat terror before".
The speech covered many of the same themes as his first address in his current five-speech series defending his administration's so-called Global War on Terror.
He outlined a newly-updated "National Strategy for Combating Terrorism" document, which includes objectives such as preventing future attacks and denying weapons of mass destruction to terrorists.
"The best way to protect America is to stay on the offence," he said.
Other goals in the US strategy include denying terrorists control of any nation or area they could use as a refuge - an aim he linked to the continued US presence in Iraq and Afghanistan.
And with less than a week until America marks the fifth anniversary of the 11 September 2001 attacks, he again portrayed US policy in Iraq as part of a broad strategy to maker the country safer.
He defended the controversial Patriot Act and terrorist surveillance programme, which involves the government listening in on calls between the US and foreign locations without the warrant which is normally required.
"If al-Qaeda is calling somebody in America, we need to know why in order to stop attacks," he said to the applause of his audience.