"It's absolutely true there are 30,000, 40,000 hard-core jihadists who would be happy to strap on a bomb right now, walk in here and blow us up."
No, that was not a quote from George W Bush.
The speaker in 2007 was presidential candidate Barack Obama, who in the same breath, also acknowledged: "We have been operating under a politics of fear…."
In the decade since 9/11, politicians of all stripes have worked the fear factor into their calculations.
Former Secretary of Homeland Security Tom Ridge said despite no evidence of another planned strike on American soil, he had to resist pressures from his cabinet colleagues to elevate the now-abandoned color-code alert system, just days before the 2004 election, which Bush narrowly won.
"I wondered," Ridge wrote, "Is this about security or politics? ... Post-election analysis demonstrated a significant increase in the president's approval rating in the days after the raising of the threat level."
'Dirty bomb' threat
Nine months after 9/11, Attorney-General John Ashcroft suddenly appeared on television to proclaim that "we have captured a known terrorist who was exploring a plan to build and explode a radiological dispersion device, or 'dirty bomb' in the United States."
But when the accused man, Jose Padilla, was eventually indicted for allegedly plotting terrorist acts, there was no mention of a dirty bomb plan. And there have been no subsequent reports of such attempts.
University of North Carolina sociologist Charles Kurzman says the recurrent specter of more mass murder has been vastly overblown, yet cannot be ignored.
"In a way," says Kurzman, "we're stuck because anyone who does relax our security posture is going to be blamed the next time a terrorist attack occurs – and there will be terrorist attacks."
Yet in a decade that saw about 150,000 murders in the US, what have been classified as terrorist strikes accounted for only about three dozen deaths, a third of them at the hands of an army psychiatrist accused of shooting fellow soldiers.
Even assuming a repeat atrocity on the order of 9/11, says Ohio State University's John Mueller, the lifetime chances of an American being killed by a "terrorist" is about one in 80,000.
That's not a statistic that usually accompanies the headlines when authorities announce they have foiled another alleged conspiracy of carnage.
But even when the plots have failed, the mass media serve as effective accomplices of those whose literal aim is to terrorise the civilian population.
"There's a bizarre relationship where they need the media," says Kurzman, "and at the same time if the media didn't cover these events we would say they are not doing their job."
Nearly half the New Yorkers who were recently polled said they do worry the city will be struck again. But the level of fear is the lowest registered since 2001.
Since then, it is economic disaster, not the dread of "terrorists", that tops the list of what keeps Americans anxious.