It was an inconvenient distraction for the Obama administration, which had hoped to use the day to reassure Americans that it had fixed the mistakes that nearly allowed al-Qaida to take down a U.S.-bound airliner last Christmas.
Clapper appeared stumped Tuesday night when asked on ABC News whether a significant terror plot uncovered in London could have security implications in the United States. The plot had received huge news coverage this week and was a major focus in the U.K., America's closest intelligence partner.
"London?" Clapper asked, looking across the table at Obama's homeland security adviser, John Brennan, who was also being interviewed.
In practice, British and American authorities work hand-in-hand on such cases regardless of how involved senior intelligence officials get. But it was an embarrassing moment for the embattled position of director of national intelligence. The job, created after the Sept. 11, 2001 terrorist attacks, has failed to live up to its billing as a central, strong overseer of the nation's intelligence infrastructure.
And the image of Clapper turning, perplexed, to Brennan, only reinforced the impression by many in the intelligence community that it's Brennan who really controls the nation's intelligence apparatus. Before his confirmation, one of the criticisms of Clapper was that he would not have the clout to take charge of the nation's far-flung intelligence network. With Brennan, a former CIA official, in the White House, and CIA Director Leon Panetta running the nation's spy agency, some lawmakers feared Clapper would be marginalized.
At a White House news briefing, Brennan said Clapper had been preoccupied with tensions between North and South Korea and helping ensure the passage of a nuclear weapons treaty with Russia.
"Should he have been briefed by his staff on those arrests?" Brennan said. "Yes."
In a city where television appearances are heavily scripted affairs and government leaders rarely get caught off guard, Clapper's misstep was as much a failure of media preparation as it was of actual intelligence. Nevertheless, it forced the White House off its message of reassurance to the American public.
The past year has been a formative period for Obama's counterterrorism strategy. After stepping up airstrikes against terrorism suspects in Pakistan early in his term, the administration has faced repeated threats at home.
Last Christmas a suspected al-Qaida operative with a bomb in his underwear slipped onto a plane bound for the U.S. and nearly detonated the device as the plane approached Detroit. In May, a Pakistani man attempted to set off a car bomb in Times Square. In October, al-Qaida in Yemen got sophisticated bombs onto cargo and passenger planes before authorities narrowly prevented their explosion.
In response, the administration has doubled the size of the nation's no-fly list. It has promised to better connect the dots to spot emerging terror threats. And it recently heightened security screenings at airports using new scanners and more invasive pat-downs.
With U.S. security officials on edge because of an increase in intelligence "chatter" about a possible attack, Brennan sought to allay concerns.
"We are in much better position today than we were last year at this time," Brennan said.
Officials have said there is no specific, credible threat this holiday season.