Three years ago, Abu Bakr al-Baghdadi proclaimed the existence of an Islamic State caliphate and proceeded to sweep his forces through northern Iraq and towards Baghdad, threatening the viability of the fragile country.

Today, the leader declaring an end to the caliphate is someone few would have imagined in the position, Iraqi Prime Minister Haider al-Abadi. A man seen as the favourite of none but acceptable to all, the 65-year-old former electrical engineer has managed to turn that tepid sentiment into a defining strength.

Over nearly three years in office, Abadi has narrowed gaps between Iraq's warring Shia and Sunni politicians. He balanced competing interests among geopolitical rivals Iran and the US, and spearheaded an overhaul of Iraqi security forces, which had fled advancing Islamic State fighters. Iraq is close to retaking Mosul, Islamic State's psychologically important stronghold.

"Abadi has magnificently shifted between leading and balancing," says Jon Alterman, director of the Middle East program at the Centre for Strategic and International Studies in Washington. "If he led too much then there'd be too many alienated people, and if he balanced too much there would be no forward progress."

Today, Iraq's security forces are on the verge of defeating Islamic State, the key requirement if the nation wants to enjoy a stable and cohesive future, despite daunting challenges that remain.