Since the Oct. 1 meeting between Iran and the P5+1 (the five permanent members of the U.N. Security Council plus Germany), the fuel-supply agreement for the Tehran research reactor has dominated expert discussion about Iran's nuclear program. This focus has obscured another potentially important but less positive development -- Iran's delay in permitting inspectors to visit its previously undeclared enrichment facility near Qom. Iran, as required by its safeguards obligations, has promised to grant the International Atomic Energy Agency (IAEA) access to the Qom facility. Although this is certainly welcome, access to the site will not be granted until Oct. 25, more than a month after Iran first acknowledged the facility's existence in a Sept. 21 letter to the IAEA.

A month may not seem like much, but it has important implications for the IAEA's ability to properly understand the nature of the Qom facility.

Iran's delay might be a shrewd political tactic to put off publication of results from next week's inspection. By the time the IAEA Board of Governors meets on Nov. 23 to receive the director general's next report on Iran, the agency will not have received laboratory analysis of environmental samples taken from equipment within the Qom facility. It is standard practice for the IAEA to use swipe samples to verify that there have been no undeclared nuclear activities at a site. This sort of environmental monitoring is critical to understanding a new facility.

However, swipe samples take weeks to analyze. Thus, Iran's delay ensures that the results of the swipe samples will not be available by the November Board of Governors meeting. By the time they are available -- probably for the first board meeting next year -- the current sense of urgency will have been lost.

Moreover, there are likely to be differences between facilities designed to produce low-enriched uranium and those for high-enriched, weapons-grade uranium in terms of layout and certain types of equipment. A month would allow Iran to hide such items and modify any blueprints requested by the IAEA.

In the longer term, Iran's delay creates a bad precedent. It sets a corrosive example that Iran -- or any other state -- can invoke if it wants to delay IAEA access to nuclear facilities. IAEA officials regularly complain about their lack of legal authority. This delay erodes the authority that they already have.

Some in the United States have been keen to blame President Barack Obama for the delay. He demanded on Oct. 1 that Iran grant the IAEA "unfettered access" to the Qom facility within two weeks. By the time inspectors are granted access it will have been three. But ultimately, Iran's ability to circumvent early inspections of the Qom facility was not Obama's fault. As director general of the IAEA, Mohamed ElBaradei is charged with leading investigations of a state's nuclear activities and was tasked with negotiating arrangements for inspections with Iran. Yet ElBaradei's reaction to Iran's delay was uncritical. He should have pursued negotiations sooner and publicly criticized Iran when it refused quick access. Given the unity among the P5+1 about the need for immediate access, this kind of public statement would have put considerable pressure on Iran.

ElBaradei and his successor, Yukiya Amano, would therefore be well-advised to be more vocal when a state delays access to nuclear facilities and to call out that state if it refuses to oblige. The task of the IAEA director general is to implement safeguards as effectively as possible. He should push hard for access and, if an impasse is reached, speak out rather than settling silently for a poor deal. Only by doing so can the director general prevent the erosion of the IAEA's authority and ensure that states take IAEA pronouncements about their nuclear programs seriously.

Nima Gerami and James M. Acton are, respectively, research assistant and associate in the Nonproliferation Program at the Carnegie Endowment for International Peace.