The issue of Iran has unexpectedly become an issue in the US presidential election.
While the Bush administration wants the UN Security Council to punish Iran for alleged deceit over its nuclear programme, President Bush's Democrat rival, John Kerry, is ready to offer Iran a deal.
The Natanz facility in Iran where centrifuges might be assembled (Image: DigitalGlobe)
With just two months to go before the US presidential election, both camps are making global leadership a key issue.
A theme of the Republican convention in New York is that Americans will be safer with George Bush in the White House than if his Democratic challenger, Senator Kerry, were to win in November.
Democrats fight back
In a speech on Monday, Mr Kerry's running mate, John Edwards, attacked President Bush for mishandling the war in Iraq and virtually abandoning Afghanistan.
At the same time, in an interview with the Washington Post, Mr Edwards staked out a new approach to Iran.
A Kerry administration would be as firmly opposed to a nuclear-armed Iran as the Bush administration is - but the two differ significantly over Iran should be handled.
Mr Edwards offered Iran a deal - a "great bargain" as he called it.
It could keep its nuclear power plants provided it gave up nuclear fuel.
By this means, America would call Iran's bluff - and maintain a united front with its European allies.
Engagement with Iran
Some US experts have used the term "grand bargain" to mean that the full range of issues on which Tehran and Washington are at odds would be put on the table.
If agreement could be reached, diplomatic relations would be resumed.
Mr Edwards did not endorse that idea, confining himself to the nuclear issue.
But in the debate over whether to isolate Iran or engage with it, the Kerry camp now seems to favour engagement.