Iran's new envoy at the United Nations headquarters in New York, Gholam-Ali Khoshroo, arrived in the US on Tuesday and met UN Secretary-General Ban Ki-Moon to present his credentials. The most senior position in Iran's political representation at the United Nations has been vacant for over a year. Iran has not had diplomatic ties with the United States since the Islamic Revolution, and its mission at the United Nations has been the only place that the two countries have had indirect contacts. Iran's previous choice for head of mission, Hamid Abu Talebi, was rejected by US law makers and US President Barack Obama due to his controversial background and the role it was claimed he had played in the hostage crisis in Tehran in the early 1980s when American diplomats were taken hostage for 444 days. Iran denied that Abu Talebi had had any involvement in the hostage crisis and said that his role had been limited to that of a translator for the hostages. However, the United States did not accept the claim and refused him a visa to come to the US. For a while Iran and the US struggled over the rejection, and Iran submitted an official complaint even though it knew that this was unlikely to succeed. In order to assuage upset hardliners made angry by the US rejection, the government of Iranian President Hassan Rouhani only presented a new nominee in January 2015. It was not easy for Iran to leave this important diplomatic position open for a year when the nuclear talks with the West were ongoing and the country needed to lobby at the UN and especially with the Americans. Iran's new choice for the mission at the UN is another US-educated diplomat. Khoshroo studied at the New School in New York and served at the mission of Iran at the United Nations and also as advisor to former president Khatami before becoming Iran's ambassador in Switzerland. Mohamed Javad Zarif, Iran's foreign minister, was looking for an uncontroversial figure to fill the position. Close to Zarif and his school of thought, Khoshroo will be in a position to assist his country's nuclear negotiation team. He comes from the same ranks as Zarif's deputy Abbas Araghchi and at the same time has family ties with Rouhani, whose niece was married to Khoshroo's son. Family ties in Iranian political dynasties are important to build trust and confidence. However, the important thing for Iran these days is the talks with the world powers over its nuclear programme, and having an expert representative in New York will give extra assistance to Zarif's team. One key issue that has remained on the table is the way the sanctions will be lifted if Iran reaches a comprehensive deal with the Western powers. Some of the sanctions were implemented by the UN Security Council, and here the skills of Iran's new representative could be particularly significant. Iran's mission at the UN during Zarif's time as ambassador was one of the most important since the Islamic Revolution, contrasting with the passivity that characterised Ambassador Mohamed Khazaie during the presidency of Mahmoud Ahmadinejad. The UN Security Council passed a number of resolutions imposing sanctions on Iran following the report by the International Atomic Energy Agency (IAEA) regarding Iran's non-compliance with its safeguards agreement. Between July 2006 and June 2010 the UN Security Council passed five resolutions sanctioning Iran for its nuclear programme. The new ambassador will have a tough mission ahead of him due to the nuclear talks deadline, approaching at the end of March, and also the public demands for improvements in Iran's relationship with the international community. Iran and the P5+1 Group (the five permanent members of the UN Security Council plus Germany) agreed last November to extend the talks and interim agreement until July, but set up a framework to reach a political agreement by the end of March and then work on the technical aspects of the agreement before the major deadline in July. The supreme leader of Iran, Ayatollah Khamenei, recently disagreed on two phases of the agreement and requested that the work should be done in one session, when, with the agreement of the Western powers, all sanctions imposed on Iran would be lifted. The negotiators will be aware that this will be difficult, since it will take time for sanctions imposed by the Security Council to be lifted. While the negotiations are ongoing and the Western powers and their Iranian counterparts are making themselves ready for the toughest and most difficult parts of the talks, all eyes are on Iran's new ambassador to the UN. Khoshroo has now to prove that the trust and support he has received from the Iranian government is warranted and that he has the ability, skills and courage to assist the Iranian negotiators at the talks next month.