Some congressional skeptics question whether a final nuclear deal with Tehran can be verified without completely dismantling Iran’s uranium enrichment infrastructure. They point to past U.S. intelligence failures to justify their pessimism. 

Past history does contain valuable lessons, but the most relevant in this case is the importance of agreed transparency measures in keeping track of a country’s nuclear activities. Preventing Iran from developing nuclear weapons requires rigorous on-the-ground inspection by the International Atomic Energy Agency (IAEA) to verify limits. And the only way to ensure such measures are in place is to conclude a comprehensive agreement with Iran. If negotiations collapse, U.S. intelligence will not be able to compensate. 

The Iraq intelligence saga is a relevant and publicly accessible example of the importance of international inspectors for monitoring nuclear activities. Once the international community forced Saddam Hussein to allow the return of inspectors in November 2002, they were able to accurately assess Iraq’s quiescent WMD programs. 

Unfortunately, the U.S. government dismissed or downplayed what the inspectors were uncovering prior to the Anglo-American invasion – on the aluminum tubes, on the activities of nuclear scientists, and on the mobile biological weapons laboratories.  

The American public now knows a great deal about the failure of its government to correctly assess the status of Iraq’s pre-war WMD activities. A presidential commission and the comprehensive reports of the Senate Select Committee on Intelligence led the way. Congress and the Executive Branch undertook a number of sweeping reforms as a consequence of the lessons learned. 

There is strong evidence that the intelligence community has stepped up its game in the wake of these reforms. U.S. detection and exposure of a secret Iranian enrichment facility at Fordow constitutes a strong disincentive for Tehran to try such gambits in the future. The 2007 National Intelligence Estimate’s finding that Iran had halted its organized nuclear weapons program in 2003 increased confidence that the intelligence community was following the evidence rather than the political winds in reaching conclusions.  

The detailed November 2011 report on the record of Iranian nuclear activities provided a reminder that intelligence agencies not only inform their own governments; they can also make important and synergistic contributions to the work of international agencies tracking proliferation. But as the world learned in the case of Iraq, there is no substitute for knowledge acquired by international inspectors on the ground, working in accordance with procedures agreed to by the inspected party. 

Significantly enhanced IAEA access to Iran is therefore one of the key objectives for the final deal under negotiation. Ensuring inspector access and other means of enhancing transparency are particularly important in this case. If Tehran chose to build a bomb, it would most likely use clandestine facilities rather than those it had declared to the IAEA, because stealth would be critical for eliminating or minimizing the reaction time of the international community.  

The six powers will therefore require in a final deal that Iran ratify and implement the “Additional Protocol” to Iran’s safeguards agreement. Tehran would thereby grant the IAEA the authority to inspect any site suspected of being used for nuclear weapons work, whether or not it had been declared as part of Iran’s nuclear program. 

The deal will also open up to regular inspection all parts of Iran’s nuclear fuel cycle – including uranium mines, fuel fabrication plants, and nuclear waste sites. These and other transparency measures under negotiation would make it much more difficult for Iran to engage in the clandestine pursuit of a weapon.  

There are still some serious issues to be resolved in the final lap of negotiations with Tehran, including the size and scope of Iran’s uranium enrichment capabilities and the duration of the agreement. But with Iran’s apparent willingness to accept enhanced, on-site monitoring by the IAEA and its awareness of the formidable technical capabilities of U.S. intelligence, “sneakout” scenarios become quite implausible. 

The verification and monitoring measures of any likely agreement will afford greater access to Iranian facilities by international inspectors than they have ever had previously. Without an agreement, the IAEA would forfeit the increased access it has temporarily gained, the U.S. intelligence community would lose confidence in its assessments, and the specter of war would loom large. 

Thielmann is senior fellow of the Arms Control Association and a former office director in the State Department's Bureau of Intelligence and Research.