Iran's relations with the West degraded as much as they improved on Monday. The day marked the beginning of a six-month initiative whereby Tehran would curb its nuclear enrichment activities and the West would regularly disburse Iranian funds frozen abroad and gradually ease its economic sanctions. The United Nations also improved its own relations with Iran, albeit briefly, by extending an invitation asking Tehran to participate in the upcoming Geneva-II Syria peace talks expected to begin Jan. 22. The United Nations has since rescinded the invitation at the behest of the United States, which along with Saudi Arabia was highly critical of the U.N. decision.

The incident reflects the difficulties Washington and Riyadh encounter as they attempt to shape Iran's detente with the international community. While the United States wants a possible rapprochement to proceed gradually, Saudi Arabia would prefer that it stop entirely. Even more important, today's back-and-forth decisions are a clear signal that whatever gains have been made between Iran and the P-5+1 group at the negotiating table, Iran still faces several hurdles before normalizing relations with the international community.

Even though the United States has encouraged the Iranian government to abandon its nuclear enrichment activities and end its support for militant political groups such as Hezbollah and loyalist forces in Syria, Washington has also worked diligently to ensure that the international community does not remove all the constraints it has placed on Iran. Indeed, the United States has tried to maintain some of its own economic and political sanctions against Iran. If Tehran finds itself completely financially and politically secure, it will have much less incentive to reach a diplomatic settlement with the P-5+1 group.

The United States has stipulated that Iran could not participate in Western-backed talks over resolving the Syria crisis so long as it supports pro-al Assad forces; the U.N. invitation contravened that stipulation. Eager to limit what they fear will be an expansion of Iranian regional and perhaps global influence, Saudi Arabia and other Persian Gulf states such as Qatar sided with the United States.

Saudi Arabia has made its frustrations with the U.S.-Iran rapprochement well known, as evidenced by Riyadh's decision to turn down a seat at the U.N. Security Council and by its proposal to expand military ties with other countries such as France. Meanwhile, U.S. Secretary of State John Kerry announced that the United States would release $550 million in frozen Iranian assets to Tehran on Feb. 1 — more important as a symbolic challenge to Saudi Arabia's regional ambitions than as a boon to the Iranian economy. Coupled with the U.N. decision to invite Iran to the Syria talks, this development shows that the momentum for normalizing ties with the Islamic republic may be growing, especially if Tehran continues to bring its nuclear enrichment practices in line with international norms, most notably by allowing inspectors access to nuclear facilities. Several countries, including EU members, India, China and Japan, are eager to normalize ties with Iran, and this eagerness makes it all the more difficult for the United States to manage the peace process. It is also what disapproving U.S. allies find alarming.

Despite Saudi Arabia's apprehension, the U.S. reaction to the U.N. invitation shows that any gains Iran has made in reaching out to the United States have fallen well short of a proper strategic realignment. While Washington has proceeded with the Iran talks, it is not completely deaf to the wishes of regional actors such as Israel and Saudi Arabia. Tehran must clearly demonstrate a willingness to behave according to internationally accepted protocols (including those governing nuclear proliferation) before it can reap the economic and financial benefits of reengaging with the international community and global economy.

Now that the United Nations has rescinded its offer to Tehran, the Iranians will respond harshly, especially since officials need to shape the perceptions of a domestic audience unwilling to be seen as fully capitulating to Western pressure. This affront to Iran comes at a time when Saudi Arabia has placed Tehran and its allies in Damascus and Baghdad on the defensive as sectarian attacks by Sunni militants and jihadists rise. We can expect mistrust to rise between certain conservative factions within the Iranian political apparatus and the West — a development that will give Iranian President Hassan Rouhani and his negotiating team less latitude as they negotiate with the West for the next six months. Perhaps most important, today's back-and-forth over the Geneva-II conference shows just how difficult the U.S.-Iran negotiations will be, not to mention resolving the Syrian crisis.