Even as most of Washington prepares to greet the new president, there are people in that city who are hard at work drawing up plans for a worst-case scenario.
They are deeply aware of the chilling possibility that looms over the transition of power from President Bush to President Obama, reports CBS News correspondent Rita Braver.
"The most urgent threat that he'll have to deal with, and other presidents after him will have to deal with, is an attack on our homeland," Mr. Bush said in his news conference on Jan. 12.
That is why the administration has been preparing an unprecedented set of scenarios for a dark day that could come to the next White House.
"In the post-9/11 world, this isn't just good manners, good government; it's a national security responsibility," said outgoing White House chief of staff Josh Bolton.
So this past week, outgoing Bolton and his Obama counterpart Rahm Emanuel took part in something that has never happened before: a mock homeland security exercise for top incoming and outgoing officials.
The premise: In the wake of train and bus bombings in London and Madrid, how would the U.S. government deal with bomb attacks simultaneously targeting transportation and other major systems in numerous American cities?
"We need to train, exercise, and execute as a team," said Homeland Security Secretary Michael Chertoff. "And we built the process based on a lot of some of the tough lessons learned over the last few years that now works."
But mock domestic attacks, such as one staged in Seattle last year to simulate how rescue workers would respond to a dirty nuclear bomb set off in an American city, are just part of the planning.
Memories of the 1998 bombings of U.S. embassies in East Africa have led the National Security Counsel to create a memo suggesting options for dealing with future attacks on U.S. facilities abroad - just one of about a dozen scenarios dealing with possible overseas crises that could impact the United States.
"As far as I know, this is the first time that policy contingency papers have been created," NSC spokesman Gordon Johndroe said, adding that his boss, National Security Adviser Steven Hadley, came up with the idea.
"Steven Hadley was here for the transition from ... I believe it was Ford to Carter ... and they were left no paper. All the safes were left empty. The Clinton administration left the Bush administration a little bit of material. But obviously the world is a substantially different place in 2009," Johndroe told Braver.
Other crisis scenarios include a major conflict between India and Pakistan, disruption of energy supplies to the U.S., or a North Korean nuclear explosion, with options for how to respond to them.
"So what we have done is created a document that goes over several scenarios of what could happen if North Korea does X, and I won't get into many details, and I think you can understand why," Johndroe said.
"What we try and do is provide the incoming team with a little bit of the history of the subject, but also some options that they could choose from if they're faced with some immediate crisis," the NSC spokesman said. "They could use them, they could discard them, but we thought it could be useful that they could see what we have come up with."
The Bush White House has laid out another key scenario, too, one that many intelligence experts believe needs immediate attention from the new president's team: A cyber attack launched from overseas to disrupt critical computer systems.
Why is it so important for the new administration to be up to speed on Day One?
"Because we're electronically undressed, and everything we do is done on an electronic network. All the information we create is created electronically," said Joel Brenner, National Counterintelligence Executive, the government's top cyber security official.
Brenner said it is unlikely that anyone could disrupt top secret government computer systems the way terrorists did in a recent episode of the television show "24."
But Brenner believes that water and sewer systems, electricity grids, air and ground traffic control, and financial markets are all possible targets.
"If instead of attacking the Twin Towers, al Qaeda had taken down a major bank, the economic consequences would have been an order of magnitude ten times greater than the economic consequences of 9/11," Brenner said. "I don't say the personal physical damage but the economic damage of taking down a system would be enormous and would reverberate through the world financial system."
In what way?
"You couldn't clear transactions, you wouldn't know who owned what in that bank anymore, and the banks all have inter-related accounting systems," Brenner said.
All this comes after many in the Bush administration came to believe that the Clinton team didn't wave enough red flags about potential threats, Braver reports. But current White House Officials say they are not just trying to be sure no one points a finger at them.
"No, I think this is an effort to provide the incoming team as much information as we possibly can, just because the world in 2009 is so different from what we found in 2001," Johndroe said. "It is moving at lightning speed. And the incoming team is going to have a lot of 'incoming' as soon as they get to the White House on Jan 20."