Ultimately, efforts to assuage Israeli and Gulf partner anxiety will need to focus primarily on very clear communication and information sharing with allies about the precise approach of the United States. This is an effective strategy the Obama administration pursued over the past few years, allowing the United States to assuage its partners’ greatest concerns and reinforce for them that Washington is deadly serious about addressing the Iranian nuclear threat. Indeed, Secretary Kerry’s last stop before heading to the Vienna negotiations last week was Paris, where he met with the Saudi foreign minister. He also worked the phones through his time in Vienna, speaking with key Gulf partners, as well as Prime Minister Netanyahu.

Another important reassurance step will be for the United States to continue to demonstrate to its allies that it is not leaving the region and that it will remain committed to combating various security concerns with military, diplomatic, intelligence-sharing and law-enforcement capabilities. The Obama administration’s decision to build a coalition to counter ISIL has gone a long way in reassuring allies in the region. Other steps, including maintenance of a robust force posture in the Persian Gulf and additional arms sales to Israel will also send a reassuring message to the Saudis in particular that despite an agreement on the nuclear issue, the United States remains committed to its regional partners.

P5+1 Unity

The unity of the P5+1 has been one of the significant diplomatic achievements of the Iranian nuclear negotiations and has played a significant role in bringing the Iranians to the table and keeping them there. But this unity cannot be taken for granted in the aftermath of the negotiations in Vienna. It is no secret that Russia and China have a different view of the threat posed by the Iranian nuclear program than do the United States and its European partners.

Following the most recent extension of negotiations, it is possible that the Russians and Chinese may begin to push more aggressively for the P5+1 to compromise in order to deliver a deal. If the negotiating partners do eventually reach a deal with Iran, the biggest challenge for the United States and the European members of the P5+1 will be to keep Russia and China on the same page about the scope and pace of sanctions relief defined in a deal.

Either way, the United States—working closely with Great Britain, France and Germany—will have to continue to make the case to the Russians and the Chinese on the importance of unity and common interests on this matter. This will be particularly true as tensions between the countries are stoked by competition in other spheres and threats by the U.S. Congress to impose new, unilateral sanctions. The threat of such sanctions that would cut off access to the U.S. economy is one of the greatest sources of leverage that American policy makers have to remind Chinese counterparts that moving too quickly to open up business with Iran could have serious consequences.

In the event that the U.S. Congress does decide to move forward with new sanctions, they will come down hard on China and Iran’s few other remaining oil buyers. They could also cause more pain for European companies with remaining commercial ties to Iran. In short, they will seriously test relationships within the P5+1 and would undermine the unity it has shown in diplomatic and economic isolation of Iran. Ultimately, this is likely to make foreign countries unwilling to participate in even harsher sanctions in the future. In turn, this will diminish the leverage of the economic-sanctions tool and may facilitate renewed ties between Iran and a variety of international actors. The implications of this for multilateral cooperation on other security files are significant, and will extend to international efforts to promote stability in the region.

Conclusion

Ultimately, trying to manage the aftermath of Vienna will be a delicate dance. It will be impossible for the Obama administration to placate hawks in Congress without raising concerns in Beijing about potential U.S. sanctions policy. Taking steps to reassure Israel will be seen by hardliners in Tehran as confirming the worst intentions of the United States. The question will be whether both Iranian and American negotiators and politicians can find the right balance, particularly if negotiations persist for even longer than currently envisioned. If they can, then diplomacy can continue and the possibility of halting Iran’s ability to produce nuclear weapons without greater confrontation remains open. But if talks fail, we might soon again find ourselves in a dangerous dynamic where Iran doubles down on its nuclear program, the United States imposes tougher sanctions, and the two sides once again lock into a collision course unlikely to end well.

Ilan Goldenberg is Senior Fellow and Director of the Center for a New American Security’s (CNAS) Middle East Security Program and formerly served as the Iran Team Chief in the Office of the Secretary of Defense.

Elizabeth Rosenberg is a Senior Fellow and Director of the CNAS Energy, Environment and Security Program and was a former Senior Sanctions Advisor at the Treasury Department.