"Young people in college were not even born when the Berlin Wall fell, and so they are not really cognizant of the Cold War and what that meant," said Valerie Plame, former CIA covert agent best known for being the subject of an identity leak.
Plame, who is included in a documentary called "Countdown to Zero" about the dangers of a nuclear world, said her work showed there is a real danger of nuclear weapons falling into the wrong hands.
"Now, truly, the genie is out of the bottle and you have the possibility that terrorists ... could be stealing a bomb or buying a bomb," she said. "The nexus of terrorism and nuclear weapons, it's absolutely terrifying."
But not everyone is convinced nuclear terrorism is as important a threat.
"Though the president keeps saying the most severe threat is nuclear terrorism, with all due respect it is not the most imminent threat," Sokolski said. "There is no specific intelligence that someone is going to steal a nuclear weapon. There is a general concern and anxiety about this, and probably it's warranted, but as to what you can do about it it's not clear."
It remains to be seen what the summit will yield. Obama met with several world leaders on Sunday, including India's Prime Minister Manmohan Singh and today will host a dinner for world leaders. By Tuesday, the administration hopes to have a working plan for each country on what they can do to make their nuclear stockpile more secure, a plan for four years from now. There will be a joint statement at the end and the president and Vice President Joe Biden will hold individual meetings and dinners with the attendees.
Obama said the summit is only the beginning of many more talks on this subject, one that he promised to tackle when he won the Nobel Peace Prize last year.