Beginning on Monday, the Nuclear Suppliers Group, or NSG – 48 countries that export most of the world’s nuclear material, equipment, and technology – will meet in Seoul to decide whether India should now be allowed to join. The United States has strongly urged the NSG to say yes.

The NSG should not say yes next week. It should tell India that there are good reasons to include it, but also that the group needs to complete an internal fact-finding and consensus-forming process in part to prepare the NSG for the consequences of possible Indian membership.

The United States has argued that bringing India into the group would be good for nuclear nonproliferation. So far it isn’t clear what the net overall benefit would be, especially because the White House is prepared to go forward without India having made non-proliferation commitments that many others in the group have made and virtually all say are important.

All NSG members are parties to the Nuclear Nonproliferation Treaty, or NPT.  For the group’s 43 states without nuclear arms, NPT membership commits them not to possess these weapons. For the five states in the NSG with nuclear weapons, NPT membership means that they have legally committed themselves to nuclear disarmament and not to assist others in obtaining nuclear weapons. In addition, NSG members have taken other important steps toward a nuclear weapon-free future, by joining the Comprehensive Nuclear Test Ban Treaty (CTBT), by joining treaties that create nuclear weapons-free zones, and/or by permitting the International Atomic Energy Agency to verify that no aspect of their nuclear programs are being used to produce uranium or plutonium for nuclear weapons.

India is a nuclear-armed state. India is not a party to the NPT, it is not a party to a nuclear weapon-free zone treaty, it will not join the CTBT, and it will not make legal commitments identical to NPT articles concerning its nuclear arms. NSG members therefore are compelled to think harder than in previous cases about what will be the consequences of admitting India into the group. Those consequences include the impact on current NSG rules that discourage assistance to nuclear weapons programs in four non-NPT countries, as well as the impact on global efforts to strengthen specific NPT norms.

For several years the NSG has pursed a “structured dialogue” to consider the case for Indian membership. When the Obama White House and India recently began pressing to close the matter, the group had discussed possible steps that India could take to strengthen non-proliferation, but India had made no commitments and the NSG had not reached agreement on what Indian membership would mean for the group’s own practices and rules.

New Delhi wants a decision now, before Obama leaves office. The desire to build a special relationship is commendable, but this should not come at the expense of the NSG’s fundamental nonproliferation mission. India may argue that not taking a decision next week will interrupt momentum in its favor. But that momentum is illusory, generated by national political leaders concerned with ties to the U.S. and India and unaware that the group’s working-level experts don’t yet agree on how the NSG should treat India’s nuclear weapons.

Ever since the NSG was set up to respond to India’s 1974 test of a nuclear explosive device using peaceful-use nuclear materials supplied from the U.S. and Canada, the NSG has aimed to inhibit assistance to India’s nuclear weapons program. Should India join the NSG, it must decide whether the NSG should continue to deny nuclear trade to India. If the answer is yes, how will it do that with India in the room? If instead the NSG will no longer restrict trade with India, or restrict it less, must it not amend its own rules and procedures? On the eve of next week’s meeting, the NSG has not yet answered these questions.

For that reason, the NSG should continue with the process of fact-finding and consensus building. That could be done in a working group led by South Korea, which will chair the group for a year beginning next week.

At the meeting in Seoul, the NSG should also tell India that delaying its decision is not a vote against India. India has an important nuclear program that NSG members want to see covered by global trade rules and therefore they see the value of bringing India into the group. Including India, the world’s most populous developing country, would demonstrate that the NSG is not a cartel of wealthy technology-owning states but is committed to global nuclear equity.

The United States advocates Indian NSG membership for commercial and geostrategic reasons largely unrelated to nuclear export controls. Neither ground justifies forcing a decision now. In 2008, the NSG elected to permit civilian nuclear trade with India, meaning that India can import a raft of reactors its wants to buy from vendor Westinghouse. If pressure from India and the U.S. over NSG membership intensifies, China, which has been hanging back, might formally block India, setting back New Delhi’s prospects for many years. Were Chinese President Xi Jinping instead to tell Obama he would allow India in without admitting Pakistan, Islamabad might respond with a nuclear escalation.

Above all, NSG members next week should recall that, unlike the NPT, the NSG is a not based on a treaty but on the shared political will of a group of states that act voluntarily and in consort with shared objectives. In looking at Indian membership, the NSG needs to consider the risk that making exceptions to its rules for one state might pose for the group’s objectives. The NSG needs find out what changes it will need to make to accommodate a state with nuclear arms outside the NPT. If the group waits until after India is admitted, and India then uses its veto power to prevent adjustments to NSG rules in response to Indian membership, the credibility and effectiveness of the NSG could be seriously damaged.

This article originally appeared in the Diplomat