Haider al-Abadi’s appointment as Iraqi prime minister in August was welcomed across the political spectrum as influencers in Baghdad realised they could not afford to give divisive leader Nouri al-Maliki another term.

Although Al-Abadi is seen as a more trustworthy character than his predecessor by the minority Sunni Arab and Kurdish communities, the prime minister has yet prove he is capable of leading the country out of the security crisis that has seen control of large areas of the country ceded to Islamic State in Iraq and Syria (Isis) militants.

Under pressure from the US, Al-Abadi has given more concessions to the Sunnis in his new government and has announced plans for a new “national guard” police force to let Sunni-majority areas handle their own security.

But Al-Abadi must also pander to hardline Shias in his parliamentary faction who would not welcome handing any military power to the Sunnis and favour battling Isis using Shia militia groups.

To add to the prime minister’s troubles, falling global oil prices are expected to see government revenues shrink in 2015 and the expansion of crude production in the south of Iraq is falling way behind schedule.

The shift in government focus to security issues should cause a slowdown in the country’s projects market, which has already been disappointing in post-2003 Iraq with the exception of the oil sector.

The formation of a unity government to lead Iraq for the next four years is a welcome progression, but significant changes to the country’s flawed constitution will be required to fix a framework exploited by Al-Maliki to concentrate power in the hands of his Shia political allies.