For the past two months the world has watched as political turmoil has deepened in Iran after the contested presidential election results that returned Mahmoud Ahmadinejad to a controversial second term.
Now those problems threaten to grip not just Iran but the wider Middle East and beyond.
We know from intelligence estimates that Iran is nearing the point when it can produce its first nuclear warhead and the means to deliver it. That moment is likely to come under the leadership of Ayatollah Ali Khamenei, the Supreme Leader, and Mr Ahmadinejad, who will be inaugurated this month for another four-year term.
These are men who have demonstrated that they intend to hold on to power by whatever means necessary. They are also responsible for accelerating the nuclear programme and taking a hardline position against the West, in spite of repeated peace overtures made by President Barack Obama this year.
Washington has given Tehran until September to respond to an offer of dialogue. The hope is that diplomacy can bring Iran back from the brink. The test will be whether it is prepared to abide by international safeguards. These would allow it to build a legitimate civilian nuclear programme, which it is doing with Russian help at Bushehr. But it would mean stricter supervision of its more suspect facilities at Natanz and Arak.
If Iran chooses not to engage with Washington and rejects a negotiated deal on its nuclear facilities then America, Britain and France will press for harsher United Nations sanctions against Tehran. These will take effect only if Russia and China, who hold the right of veto at the UN Security Council, drop objections to tighter economic measures.
At this point the future looks bleak. If diplomatic efforts fail and if Iran presses ahead with its ambitions, then the Middle East may be headed for the most serious conflict in decades. Israel’s policy is that it prefers a diplomatic settlement but that “all options remain on the table”. By that it means using force to destroy Iran’s nuclear facilities, probably with air and missile strikes. Iran would be likely to respond and within days the region would threaten to become embroiled in a terrible war.
Many doubt that Israel would be prepared to take such a dangerous step, particularly since experts believe that Iran has the ability to rebuild the key uranium enrichment site within two to three years.
Who runs Iran in the coming months and years is not just a matter for Iranians.
This is now a global issue.