Iran will assert its right to "peaceful" nuclear technology although it'll stay within the rules of the Nuclear Non-Proliferation Treaty (NPT) and International Atomic Energy Agency (IAEA).

However, the tensions' real source is the United States' relentless military build-up in the Gulf, where it's mobilising a ready-for-assault flotilla led by two aircraft-carriers.

President Bush has ordered US troops to "seek out and destroy" Iranian "networks" in Iraq. US strategy towards Iranian suspects has shifted from "capture and release" to "capture or kill." The "surge" of 21,500 US troops in Iraq will probably be directed at Iranian targets. The "Patriot" missiles being sent are certainly meant for Iran.

The US has launched a daily barrage of propaganda alleging that Tehran is providing Iraqi insurgents lethal weapons like "explosively formed penetrator" devices. It claims Iranian EFPs have killed 170 Americans since June 2004. Iraq's No. 2 US general says his troops have captured arms whose Iranian "serial numbers."

This defies credulity. A country which manufactured a particular weapon need not be its provider. Iran fought an eight year-long war with Iraq. Iraq has many Iranian-made weapons -- within a massively armed population.

The US "evidence" on Iran is even flimsier than the "sexed-up" 2002-3 dossiers on Iraq's nuclear weapons, which undermined Washington's credibility.

Iraq's Shias aren't at war with America. The two main Shia militias are controlled by leading parties in the ruling pro-US coalition. It makes no sense for strongly-Shia Iran to arm Iraq's mainly Sunni insurgents who proactively target US troops.

Meanwhile, the US is making other provocative moves, including aggressive air-patrolling along the Iran-Iraq border. The provocations could escalate, or can be engineered into, into conflict.

Washington's approach to Iran is driven by prejudice and hostility, some of it rooted in the Islamic Revolution -- itself a reaction to the US's imposition of the Shah. The US is convinced Iran wants to become a hegemonic regional power -- and a nuclear weapons-state (NWS).

That's why President Bush in January 2002 called Iran an "Axis of Evil" state -- despite the helpful role it played after September 11. Iran backed the US invasion of Afghanistan. It has always opposed al-Qaeda.

Without Iran's mediation with the Northern Alliance -- which it backed against the Taliban -- it's doubtful, says the latest Newsweek, if Mr Hamid Karzai would have become President.

The US has a paranoid, exaggerated view of Iran's nuclear activities and ambitions. Iran has a primitive pilot plant-scale nuclear program based on uranium enrichment. It's not clear that it can graduate to industrial level. In addition to 328 centrifuges last year, Iran claims to have installed another 328 -- when several thousands are needed to make a few bombs.

According to an International Institute of Strategic Studies (London) report, Iran's basic problem lies in converting uranium yellowcake into pure hexafluoride gas. The gas is probably too contaminated to be centrifuged.

Centrifuges aren't easy to master either. These delicate machines spin at ultra-high speeds like 1,200 revolutions per second. Even India has had trouble in mastering centrifuges. Besides, in earthquake-prone Iran, even mild tremors can damage centrifuges.

Iran is probably 3 to 10 years away from the Bomb.

However foul Iran's intentions -- do any of the NWSs have honourable intentions? -- and despite its record of concealment of some nuclear activities -- for 18 long years -- Iran is in no material breach of its NPT obligations. The IAEA has found no diversion of nuclear material to military uses.

The international community's best bet lies in holding Iran down to its commitment to putting all its nuclear activities under strict inspections. But the US and Israel think otherwise. They have drawn up plans for attacking Iran's nuclear installations, and its main military facilities too.

According to The New Yorker and The Sunday Times, the US and/or Israel may even use "tactical" nuclear weapons. Mr Bush is under strong neo-conservative pressure to attack Iran -- to bring about "regime change".

An attack on Iran will have catastrophic global consequences, including a conflagration in the Muslim world. Billions of citizens the world over will turn against the US.

An attack will guarantee that Iran develops nuclear weapons. Bombing Natanz and Isafahan will set the nuclear program back by five years. It won't destroy Iran's capacity to rebuild the facilities.

Fifteen British think-tanks and civil society groups, including the Oxford Research Group and Foreign Policy Centre have produced a report "Time to Talk", which says that war on Iran will create unprecedented instability. It "would be perceived … as aggression towards the Muslim world, fuelling anti-Western sentiment and giving … impetus to extremists."

War on Iran will produce "havoc in the global oil market" and send "oil prices over $100 per barrel." A $10 increase could prune Sub-Saharan African GDP by 3 percent and push developing countries into "greater poverty."

War will also have grim environmental effects, including severe radioactive contamination, oil slicks and oil-well fires.

The impact on Iranian civilians will be "acute." "Iran's nuclear facilities are located near densely populated towns, and those living or working nearby would be at serious risk." If military assets are attacked, there could be thousands of deaths.

An attack will probably further jeopardise "the prospects of peace taking root in the Middle East", especially in Palestine-Israel, and severely undermine hopes for stability in Iraq.

Iran can create massive trouble for the US in Iraq. Within Iran itself, an attack will bolster hardliners and set back the chances of reform -- just when President Ahmedinejad's position is getting weaker and the reformists' stronger.

It's not clear if many states can and will restrain the US. But civil society mobilization against war on Iran has become indispensable.

Praful Bidwai is an eminent Indian columnist.