If the U.S. wants to improve relations with Iran, it can happen only with the approval of Ayatollah Ali Khamenei.
He is Iran's supreme leader, with all the power that the job title suggests. He controls everything from Iran's nuclear program to full authority over foreign policy.
"Only the supreme leader of the country is involved in negotiations with the United States," says Tehran political analyst Said Laylaz.
The Omnipresent Leader
Khamenei is less famous in America than President Mahmoud Ahmadinejad, whose rhetoric about the U.S. and Israel has made headlines.
But it's Khamenei's picture — not the president's — that has been plastered all over Iran since 1989, when he succeeded the revolutionary leader Ayatollah Ruhollah Khomeini.
Billboards, posters and office portraits often picture Khamenei alongside Khomeini's scowling face.
The newer leader's face seems more benevolent by contrast, with a white beard and thick glasses. His expression is often studious and sometimes smiling.
That face overlooks public squares, hallways and private rooms. If passengers on a domestic flight should happen to look up during the safety announcement, they may spy Khamenei peering over the flight attendant's shoulder — his portrait hangs by cockpit doors. Iranians don't leave home without him.
Khamenei's Early Years, Influences
Iran's supreme leader grew up in the eastern city of Mashad. It is best known for the Shiite Muslim shrine of Imam Reza, a giant complex topped by a golden dome, a short distance from the alley where Khamenei's father had a house.
The house has now been turned into a place for Shiite rituals. The rooms have been preserved, and on a recent evening, old men and young children prayed on the floor of his childhood bedroom.
It was one of four bare rooms in a modest home. Ali Khamenei grew up the son of an ayatollah, a religious leader with an exalted title and a limited income.
The son attended theological school and came under the influence of Ruhollah Khomeini, the older cleric who would come to dominate Iran's Islamic Revolution.
The younger man returned to Mashad and attracted revolutionary followers of his own. One of them was Hamid Reza Taraghi, who was arrested by the government of the Shah of Iran.
When he was released from prison, Taraghi recalls, Khamenei told him "the path of fighting is a long hard road."
The Ayatollah's Ascension
The leader's rise to power was long and slow. After the 1979 revolution, he became the country's president, then supreme leader when Khomeini died.
Karim Sadjadpour, an Iranian-American who studies Khamenei at the Carnegie Endowment for International Peace, notes the interesting way in which the ayatollah rose to power.
"He wasn't elected because he was necessarily the most qualified person to take over for Ayatollah Khomeini, but he was essentially a default choice, someone that all of the different factions could agree upon, loyal to the ideas of the revolution," Sadjadpour says.
Once his fellow clerics had agreed upon him, Khamenei gave an inaugural address, modestly saying he was no more than a minor cleric.
Yet for 20 years, Sadjadpour says, he has been putting his supporters into almost every position of power.
"He actually has much more control than an American president in the sense that he also has control over the media. He has control over the judicial, the legislature," Sadjadpour says.
"[Khamenei] likes to project this image of a magnanimous grandfather who is simply guiding the country benevolently. But in reality, behind the scenes nothing can get done without his consent, and if you cross him he can be extremely vindictive," he says.
Multiple Bases Of Power
Visitors to Tehran may see one source of the supreme leader's power on the streets. Outside the British Embassy last month, demonstrators arrived waving banners. They were protesting a decision by the European Union involving an Iranian opposition group.
The men are members of the Basij, a militia force that's known to appear anywhere the regime needs a little bit of muscle — whether to mount a protest against the West, to denounce Israel, or to put pressure on individual Iranians.
The militia is under the supreme leader's authority, as are the Revolutionary Guards, a military force that's increasingly involved in business.
That brings up another source of Khamenei's power: He appoints men who hold tremendous influence over Iran's economy.
During the 1979 revolution, Iran's new Islamic rulers seized massive assets previously controlled by the deposed Shah of Iran. The money was channeled into charitable foundations, which now comprise "one of the biggest conglomerates in the world," according to Sadegh Samii, a Tehran businessman.
These conglomerates are invested in beverages, banks, automakers, agriculture and steel, among other industries, says Samii.
Ayatollah Khamenei selects the men who decide where that money goes.
Opposition To U.S. Defined Revolution
A few weeks ago, Khamenei's advisers completed a long-term development plan, which came at a critical time, since the economy is sliding toward crisis.
Taraghi, the longtime follower from Khamenei's hometown, remains an official in the supreme leader's political party. He says Khamenei insisted on one major change: making it a top priority to ensure that any development is Islamic. For example, he wants to make sure any new buildings have a traditional Iranian character, not Western.
Khamenei is guardian of a revolution founded in resistance to the United States, and at a recent session of Friday prayers in Tehran, some of the worshipers chanted, "Death to America! Long live Khamenei!"
The supreme leader has rarely met with Americans, although he did once sit down with John Bryson Chane, the Episcopal bishop of Washington, D.C.
Last year, Chane was attending a conference on religion and politics in Tehran. "Out of the blue, somebody came over and said, 'You're going to meet the supreme leader. Be out in the hallway in 10 minutes,'" he recalls.
Chane and a handful of other Westerners went to meet the leader in a room across town.
"It had a beautiful Iranian woven Oriental rug. There were chairs along the wall. ... And he speaks very softly, so it's not a matter of sitting around the table, you know, hammering out stuff. It was a very quiet conversation," Chane says.
In that quiet voice, Khamenei spoke of his country's historic involvement with the West.
"He said it had been hurtful," Chane says. "It had inhibited its ability to become an independent nation. ... It was unwelcomed."
Future Of U.S.-Iran Ties Uncertain
Now, one key question is whether Khamenei would welcome contacts with American officials to resolve their concerns about issues like terrorism and Iran's nuclear program.
For many years now, Khamenei's answer to that question has been found on a gigantic mural that's painted on the side of building in Tehran.
The mural is of an American flag, although the stars have been replaced by skulls.
Beneath the flag is the slogan "Death to America," and beneath that, a quote attributed to Ayatollah Khamenei: "We will not get along with America even for one single second."
However, an Iranian politician and presidential candidate, Mehdi Karrubi, says he thinks that's an old position.
"If America shows its good will," Karrubi predicts, "we will respond positively."
In Washington, analyst Karim Sadjadpour is not certain that Khamenei will allow that.
"I don't think he wakes up in the morning saying, 'How can we have an amicable and expansive relationship with the United States?" he says.
The Iranian Revolution is 30 years old, and Sadjadpour says three symbolic pillars of that movement remain: enmity toward the United States, enmity toward Israel, and the symbol of Islamic piety, the hijab, or the Muslim code requiring women to dress modestly.
If Iran were ever to drop its opposition to America, Sadjadpour says, "then what is the essence of the Islamic Republic? What remains?"
The analyst notes that Khamenei is almost 70 years old. "I don't expect him to abandon or deviate from a political philosophy, which he has held very strongly now for four or five decades."
That's why one diplomat cautions that Iran's supreme leader remains just as much of a hard-liner as the "Death to America" mural would suggest.