The protocol, based on a model outlined in the IAEA's Information Circular 540, calls for inspectors to have virtually unfettered access to any facility. After the first Gulf War, when the true scope of Iraq's nuclear ambitions came to light, the IAEA realized that weapons inspections were too lax, since inspectors had access only to a pre-approved list of sites. As a result, the IAEA came up with a new safeguarding system called "Program 93+2"—the first figure in reference to the year it was hatched, the second in reference to the two years the organization hoped it would take for the system to go into effect.
Details of the new safeguards weren't settled on until 1997, when they were published in INFCIRC 540. The protocol gives inspectors more or less free rein to follow up on leads about covert facilities, or to interview scientists who might possess valuable information about illicit arms programs.
Iran, however, is hardly the only nation to have dragged its feet on implementing the additional protocol. In theory, all of the IAEA's 136 members should have no problem approving the revised safeguards. But only 73 nations have signed the protocol, and only 35 of those countries have actually implemented the new agreement. That's no great concern when it comes to the likes of San Marino or Tonga, but the holdouts also include nuclear powers such as India, Pakistan, and Israel, which have yet to sign, and the United States, France, and Russia, signees who have yet to implement the prescribed changes.
Iran has hinted that it might sign the protocol in exchange for the lifting of trade restrictions on so-called dual-use materials—that is, nuclear equipment that can be used for peaceful reactors as well as weapons plants. The United States, however, has indicated that it will not lift its sanctions and will continue to put considerable pressure on other nations to refrain from selling Iran such materials.
Explainer thanks Jean du Preez of the Center for Nonproliferation Studies and George Perkovich of the Carnegie Endowment for International Peace.