Iran - An Uneasy Neighbour
As a result, Islam came to play a central role in government. All legislation has to be approved by the supreme Islamic jurisprudent and the Council of Guardians to ensure that it is in accord with Islamic law. Under the Shah, the country had looked to the West for orientation.
Although about twenty percent of the world's population is Muslim, they do not form a homogenous group. Different branches like the Sunnis and the Shiites emerged, each with distinct traditions. The Shiites tend to hold a grudge against the Sunnis, but all believe in the one Koran and the prophet Mohammad.
Historical differences
Iran's approach to politics and its interpretation of Islam, for example, is very different to the Taliban's in Afghanistan. Iran is Shiite, the Taliban Sunni. Iran in fact opposes the Taliban regime, and backs the Northern Alliance, in control of about five percent of Afghanistan.
Iranians do not share the Taliban's taste for war or their drive to conquer all of Afghanistan. They also resent the Taliban's restrictions on music and celebration. And Iran's anger with the US has historical reasons.
All about oil
Iran's problems with the US go back to 1953. A CIA operation toppled the democratically elected government, which had nationalised Iran's oil industry. The coup brought the pro-Western Shah back to power, who promised to deliver oil on US terms.
The move was seen to show America's ruthlessness, when it came to protecting its interests in Iran's oil. Oil generates about 80 % of the country's revenue.
The people's deep-seated anger over US intervention in Iranian affairs is still there. And they mistrust US intentions.
Change
More recently Iran began to adopt more moderate policies. This trend has accelerated under the leadership of the present ruler, Mohammed Khatami.
Iranians have stopped shouting "death to America" after prayers. And they condemned the attacks on New York and Washington.
But Iran made it clear early in the crisis that it would not give the US any military support or join President George W. Bush's "coalition". It insists any action must be taken under United Nations auspices.
Iran and the US coalition
Several factors are important in considering whether Iran would ever join a US led coalition. The definition of terrorism is a major problem.
Both the Lebanese and the Palestinian causes are legitimate struggles, constituting resistance rather than terrorist movements, according to the Iranians.
Russia and Iran are also worried about allowing the US to exploit the "war on terrorism" to get a bigger military foothold in the region, perhaps ending up with permanent US bases in Uzbekistan or Afghanistan itself.
In spite of its hard line, Iran finds itself in an uneasy alliance with the US on the ground, now that Washington has decided to step up support for the Northern Alliance of anti-Taliban forces.
Iran and Russia have long been the Northern Alliance's main arms suppliers.