Two decades ago Mahmoud Ahmadinejad entered Iraq, then operating behind enemy lines as a special forces commander in the Revolutionary Guards on a sabotage mission to the oil-rich city of Kirkuk.

Next month he will embark on a very different voyage when he will be greeted with full honours as the first Iranian President to visit Baghdad since the Iranian Revolution in 1979. The visit presents both an opportunity to improve relations between the two neighbours and a risk that old sectarian frictions could be reignited if diplomacy fails.

For its part, the Iraqi Government, headed by Shia Muslim brethren of Iran, is keen to lay to rest the centuries of suspicion between Arab and Persian, particularly the legacy of the Iran-Iraq War that claimed the lives of a million people on both sides.

America, too, will be following the proceedings closely. It has already held bilateral talks with Iranian officials in Baghdad on settling outstanding issues. It remains deeply suspicious about Iran’s intentions but claims to be keeping an open mind about President Ahmadinejad’s arrival.

The big question regards what the mercurial Iranian leader wants out of the visit. To date he has used public occasions to berate America and the West, to boast about his country’s newly acquired nuclear technology and to leave few in doubt that Iran is intent on spreading its revolution across the region.

Pursuing this policy on Iraqi soil could be very counterproductive. The country’s Sunni Muslim community is deeply suspicious of Iran’s intentions. They are supported by most Arab governments and increasingly their opinions are being listened to by the Americans, who remain the main power in Iraq.

If President Ahmadinejad presents a more moderate face, as he has shown capable during visits to Saudi Arabia and other Gulf states, there is a chance that a real opportunity could present itself not only to heal old wounds with Iraq but begin the process of improving ties with America.

Times Recommends

• Air crash: ‘Everything is burnt. It is the closest thing to Hell’
• The true story of a passionate Korean 'spy'
• I shot Lennon in the back, Chapman tells parole board