Reza Marashi writes: After weeks of hyping intelligence on the military aspects of Iran’s nuclear program, the Obama administration’s public statements on the recently released International Atomic Energy Agency report are curiously moderate. Off the record, U.S. officials say that not all of America’s intelligence findings were included in the I.A.E.A. report — which aims to reflect international consensus. This fact speaks to a larger challenge — that the United States faces a credibility problem. Key countries do not share Washington’s assessment of Iran, and thus it’s unlikely that the U.S. will disclose more substantial information.

Some administration officials would like to see harder evidence made public — if for no other reason than supporting calls for more “crippling” sanctions on Iran. But U.S. intelligence agencies reportedly oppose more detailed disclosures for fear of jeopardizing intelligence-gathering and sources. The U.S. is therefore unlikely to secure more robust U.N. sanctions when it makes its case to the Security Council.

More important but less understood, however, are two longstanding and increasingly dangerous institutional problems within the U.S. government that this case has brought to the fore: an overreliance on intelligence and under-utilization of diplomatic resources when formulating Iran policy. By treating diplomacy with Iran as a reward to be earned rather than the vital national security tool that it is, American politicians have been administering a self-inflicted wound.

The recent allegations against Iran show the critical role that intelligence can play in helping policymakers gather information and make decisions on the most challenging issues. However, intelligence is not meant to be taken in isolation — and when it comes to America’s Iran policy, it almost always is.

While serving in the State Department’s Office of Iranian Affairs, I learned the 10 percent rule: intelligence is meant to make up approximately 10 percent of the overall information used to analyze strategic issues. The remaining 90 percent consists of embassy reporting and unclassified, open-source information.

As a whole, this symbiotic process is meant to provide a balanced, broader context to policymakers. Intelligence is supposed to be the missing piece of the puzzle — not the only piece. Overreliance on intelligence to support key policy decisions results in skewed or incomplete analysis that lacks the fuller context needed for sound decision-making. As this information vacuum grows over time, so too does the likelihood of misperceptions, miscalculations and dangerous mistakes.

Intelligence is not a substitute for the critical work of diplomats on the ground — and perhaps no foreign policy issue demonstrates this more forcefully than Iran. Simply put, a vital national security process has been broken for over three decades, and American politicians are exacerbating rather than repairing it.