The Iran nuclear deal signed in Vienna on 14 July represents a historic breakthrough in political relations between Tehran and Washington, but widespread rapprochement in relations looks unlikely.
Geopolitical divisions in the Middle East see the two countries with opposing interests in many of the key regional conflicts, while the mutual relationship of mistrust is rooted deep within the leadership of the two countries.
Nowhere are these opposing interests more apparent than Syria, where support from Iran and its Lebanese militant proxy Hezbollah are an essential part of the network holding Syrian President Bashar al-Assads regime in place. Meanwhile, the US and its regional allies Saudi Arabia and Turkey have backed armed organisations fighting to remove Al-Assad from power.
Tehran and Washington also fall on opposing sides in the conflict in Yemen, where a coalition of US-backed Arab powers are attempting to drive out the Houthis, which the US claims is backed militarily by Iran.
Many US sanctions against Iran will remain in place after the Vienna deals implementation. These sanctions were enacted by US Congress in 1995 as measures to punish the Islamic Republic for its alleged support for terrorism in the Middle East, along with its human rights record.
The nuclear deal may represent high point in modern US-Iranian relations but there remains an entrenched distrust within the political establishments of the two countries.
Irans head of state and supreme leader Ali Khamenei repeatedly stated that he does not oppose negotiations with Washington on the nuclear issue but it remains to be seen whether dialogue on other issues will be allowed to follow.
The icey relationship between the two countries is long and complex. Antagonism has stemmed from a series of events including the CIA-orchestrated coup of democratically-elected Prime Minister Mohammad Mossadeq in 1953 through to the US embassy hostage crisis in the 1979-81 aftermath of the Islamic revolution.
In 2002, former US President George Bush denounced Iran as part of an axis of evil, causing outrage in Iran, while the same year the US accused Tehran of pursuing a clandestine nuclear weapons programme.
There is a strong hardline influence in Iran that opposes any rapprochement with the US, just as there is an influential anti-Iran voice in Washington both will create obstacles to reestablish trust between the two powers.