The principal reason that nations want to acquire nuclear weapons is for security. They perceive some threat—whether nuclear, chemical, biological, or conventional—that they believe will be best handled by having a nuclear deterrent. In the past, nations have also been motivated by desire for prestige, but today this plays a lesser role given the high political cost of weapons possession. Additionally, force projection has also been a motive. Saddam Hussein, for example, not only sought nuclear weapons partly to counter Israel’s nuclear arsenal but also to support its hegemonistic advanees toward Kuwait, Iran, and others. Security assurances can do little to dampen the motivations for prestige or force projection, but they can be very effective in lessening the security concerns that may foster nuclear proliferation.