The Present Danger
“We bear a special responsibility for the security of nuclear weapons and fissile material, in order to assure that there is no possibility such weapons or materials fall into terrorists’ hands.”
—President George W. Bush and President Vladimir Putin, joint statement 
According to the Nuclear Threat Initiative (NTI), Co-Chaired by Ted Turner and Sam Nunn, former Georgia Senator and chairman of the Senate Armed Services Committee, the most difficult step in making a nuclear bomb is obtaining plutonium or Highly Enriched Uranium (HEU). It is much easier for terrorists to transport and detonate a nuclear bomb than it is for them to obtain the fissile material or a bomb itself. For us, preventing the theft or illegal purchase of fissile material is much easier than stopping terrorists from transporting and detonating a bomb.
Consider this quotation from the research library at the NTI’s website:
…the amounts needed to build a bomb are small. With an efficient implosion design, a baseball-sized lump of plutonium weighing 4 kilograms [about 10 pounds], or a softball-sized lump of HEU weighing perhaps 3 times as much, is enough. …a worker at a nuclear facility could put enough material for a bomb in a briefcase or under an overcoat and walk out.
The necessary conditions for a global “perfect storm” have formed: porous borders, ease and speed of internet communications, advances in technology, ready access to information on building complicated WMDs, ability to manufacture or obtain the materials, and the declared intent of terrorists to use them. All that terrorists’ need is the ingredients to make WMDs, if they don’t already have them.
 NTI Annual Report 2004: 16. http://www.nti.org/b_aboutnti/annual_report_2004.pdf