DUBAI, United Arab Emirates — In just three years, the Iraqi prime minister, Haider al-Abadi, has rebuilt the army, defeated the Islamic State and restored sovereignty across this deeply divided nation, accomplishments that, in the eyes of many, give him the stature of an Iraqi Abe Lincoln.

Still, as Mr. Abadi is quick to warn in weekly addresses to the nation, stability remains fragile.

The country is coping with an ever-bubbling threat of violent sectarianism between the Shiite and Sunni populations, as well as endemic government corruption and overwhelming economic despair, especially among millions of citizens left homeless after the battles against the Islamic State.

This is a crucial moment for Iraq as it gears up for an election that could undo its hard-fought gains. The vote could also reshape the influence of Iran across the Middle East and determine the likelihood of a resurgent Islamic State.

But it’s an important moment for Mr. Abadi, too. He has never spearheaded an electoral campaign, and has already stumbled as he tries to negotiate the mind-numbing complexities of Iraqi politics for a vote that will test his own political acumen in a challenging security environment.