Alliances can be so mercurial in this region that Western journalists have worn out the clich "the shifting sands of the Middle East."
So it is rare when one country becomes locked-in as an enemy, or as a friend. But Iran has been firmly on the enemy list since Ayatollah Khomeini led the Islamic Revolution in 1979, promising death and terror for the "Great Satan," the United States.
Few forget how young radicals took 52 Americans hostage at the embassy here for 444 days. Today Iran is considered by the US to be the most dangerous terrorist state.
But the landslide victory of Mohammed Khatami, a relatively liberal cleric, in May presidential elections may presage a different future. "We would like to end the estrangement," a White House official told the Los Angeles Times in July. "And we are now looking for ways to accomplish that goal."
Iran's foreign minister, Ali Akbar Velayati, has not ruled out dialogue: "If they [the US] send a message to us through their interest sections [at the Swiss Embassy], it will not remain unanswered."
Iranians have long considered US isolation of their country to be ham-handed, though a German court earlier this year found that Iran's leadership had issued direct orders to assassinate opponents of the regime in Berlin. Extremist cells still operate independently of more moderate leaders.
In Tehran, an Iranian diplomat with long experience in the US candidly explains why he believes Iran should now be part of the "shifting sands."
"Maybe on the first day of the Revolution we did crazy things, and we feel ashamed," the Iranian diplomat says. "But you can't base your decisions on events of 20 years ago. We were anti-US on day one, yes. Given the situation then, after so many years of American manipulation in Iranian politics with the Shah, yes.
"Exporting the revolution is over. You can't go back to day one and be taken seriously anymore.
"Of course religion influences Iran. But what is the influence of religion on Israeli policy? Israel declares Jerusalem its spiritual capital, they put their beliefs into action, and get US support for everything.
"Why is America so worried about Iranian influence, when there are 10 McDonald's fast-food restaurants in Azerbaijan, and every yurt in Central Asia has a Michael Jackson cassette tape?
"You are ready to forgive Vietnam, though tens of thousands of Americans were killed there - because it is in your interest. And you forgive China for all its human rights abuses so you can trade there.
"But you are not ready to forgive Iran. You still think you must teach us a lesson. How can you judge us from events of 20 years ago?" he asks.