Iranian Foreign Minister Mohammad Javad Zarif at the United Nations building in Vienna. (Carlos Barria/Reuters)

Eric Edelman, undersecretary of defense for policy from 2005 to 2009, is a scholar in residence at Johns Hopkins School of Advanced International Studies. Ray Takeyh is a senior fellow at the Council on Foreign Relations.

After two years of painstaking diplomacy, the Obama administration has finally concluded a nuclear agreement with Iran. A careful examination of the Joint Comprehensive Plan of Action (JCPOA) reveals that it concedes an enrichment capacity that is too large; sunset clauses that are too short; a verification regime that is too leaky; and enforcement mechanisms that are too suspect. No agreement is perfect, but at times the scale of imperfection is so great that the judicious course is to reject the deal and renegotiate a more stringent one. The way for this to happen is for Congress to disapprove the JCPOA.

Prior to the 2013 interim accord, the Obama administration’s position rested on relatively sensible precepts. The United States insisted that, given Iran’s practical needs, it should only have a symbolic enrichment program of a few hundred centrifuges, and that the Islamic republic could not be considered a member of the Nuclear Non-Proliferation Treaty (NPT) in good standing until it secured the trust and confidence of the international community in the peaceful nature of its program. These were not just U.S. aspirations but also the position of members of the “P5+1” powers — the five U.N. Security Council members plus Germany.

These prudent parameters were overtaken by a cavalcade of concessions that began in 2013. The administration soon brandished the notion of a one-year breakout period that would allow Iran to maintain a substantial enrichment apparatus, in effect abandoning the goal of preventing development of an Iranian nuclear capability in favor of managing its emergence. The much heralded one-year breakout period will only shrink over time as the JCPOA concedes that Iran can begin phasing out its primitive centrifuges in favor of more advanced ones. Even more troublesome is the agreement’s stipulation that after its limits expire, the “Iranian nuclear program will be treated in the same manner as that of any other non-nuclear weapon state party to the NPT.” This means that Iran can proceed with the construction of an industrial-sized nuclear infrastructure similar to that of Japan. At that time, Iran could easily sprint to the bomb without risking timely detection.

In the coming weeks, the administration will justify its concessions by professing that the agreement establishes an unprecedented inspections regime. The verification measures of the JCPOA rely on “managed access” whereby the International Atomic Energy Agency has to first offer credible evidence of untoward activity and then negotiate with Iran for timely access to the suspect facility. This certainly falls short of the inspection modality pledged by Energy Secretary Ernest Moniz, the administration’s chief nuclear physicist, who said in April that “we expect to have anywhere, anytime access.” Under the current arrangement, the likely response to Iranian mischief will be prolonged negotiations mired in arcane detail over at least a three-week period.

In as little as a few months, Iran will for all intents and purposes no longer be a sanctioned country. Although elaborate and protracted procedures are in place for the re-imposition of the U.N. Security Council sanctions resolutions, the economic sanctions imposed by the European Union and the United States — always the most essential ones — will be rolled back quickly and will not be easily reconstituted. The European oil embargo, international banking restrictions and efforts to segregate Iran from the global economy will be suspended. And the notion that U.S. business will be left out of the commercial march to Iran because congressionally imposed U.S. sanctions will remain in place is itself undermined by a loophole in the deal allowing “non-U.S. entities that are owned or controlled by a U.S. person to engage in activities with Iran that are consistent with this JCPOA.”

The JCPOA stands as one of the most technologically permissive arms-control agreements in history. All is not lost, however, and with sensible amendments the accord can be strengthened. The United States should return to the table and insist that after the expiration of the sunset clause, the P5+1 and Iran should vote on whether to extend the agreement for an additional 10 years. A majority vote every 10 years should determine the longevity of the agreement, not an arbitrary time-clock. Further, the JCPOA has usefully stressed that all of Iran’s spent fuel from its heavy-water reactor will be shipped out permanently. A similar step should be taken with Iran’s enriched uranium. The revised agreement should also limit Iran to the first-generation centrifuges and rely on “anytime, anywhere access.” These and other such measures could help forestall an Iranian bomb and stem the proliferation cascade in the Middle East that this agreement is likely to trigger.

At this late date, the only way that the agreement can be reopened and amended is for Congress to first reject it. At that time, the Obama administration or its successor can return to the table and confess that given the absence of a bipartisan foundation of support in the United States, key provisions of the agreement have to be reconsidered. At the end of such a process, the United States may yet be able to obtain a viable accord that reliably alters Iran’s nuclear trajectory.