It has been nearly a year since the signing of the Joint Comprehensive Plan of Action (JCPOA), a historic agreement that after years of negotiation was meant to walk Iran back from the brink of “going nuclear” and reintegrate it into the global economy. Although Iran has abided by the terms of the agreement, the country has yet to feel the economic relief that it was promised in exchange for constraints on its nuclear program. Iranian optimism surrounding the prospect of economic relief is turning to impatience. Given Iran’s upcoming 2017 presidential elections, advocates of the JCPOA better hope that impatience does not turn to resentment, which could cost President Hassan Rouhani the election and jeopardize the fate of the JCPOA. While it is often difficult to parse reasonable criticisms from Iran’s standard litany of anti-U.S. rhetoric, complaints that the United States is not upholding its end of the deal are not entirely unfounded. It has long been understood that the bulk of the new trade and investment that Iran could expect under the JCPOA would not come from the United States, given the extensive web of U.S. sanctions that would remain in place, but from Europe, Russia and China. However, as fear of U.S. sanctions united the international community in pressuring Iran to come to the negotiating table, the United States has a significant role to play and interest in ensuring that Iran can re-enter the global economy, as the deal’s long-term sustainability depends on it. If foreign businesses are expected to invest in and engage with Iranian companies, it is up to Washington, not Tehran, to make clear that Iran is “open for business.” Although several months have passed since the lifting of sanctions and Tehran’s hotels are reportedly full of foreign delegations eager to enter the Iranian market, the windfall of relief has not arrived. A major impediment to that windfall is persistent fear of U.S. sanctions on the part of foreign companies and banks, especially in Europe, where memories of hefty fines and penalties still loom large in the minds of many. Washington has refused to issue more explicit guidance to foreign companies about how to avoid running afoul of the myriad remaining and new sanctions, despite requests from the EU and other governments. The opacity that helped make sanctions successful in the first place is now proving to be a serious obstacle. Without a concerted effort from the United States to provide clarity and reasonable assurances to foreign businesses and banks, Iranians may be left holding their breath for a very long time. Facilitating Iran’s reintegration into the global economy is not a favor to the people of Iran or the Rouhani government, it is a commitment implicit in an agreement that U.S. diplomats and their P5+1 counterparts worked tirelessly to reach. More importantly, it is vital to the durability and success of the JCPOA, and in turn, the prevention of a nuclear Iran.