BAGHDAD — In making the optimistic case for the development of democracy here, American officials typically point to the 2010 parliamentary elections, which were judged largely free and fair by international monitors including the United Nations. But with the arrest of the head of Iraq’s election commission, the prospect for fair elections has been thrown into question.

Faraj al-Haidari, chief of the Independent High Electoral Commission, spent most of the weekend in a jail cell after being arrested on corruption charges on Thursday. He was released on Sunday afternoon after posting bail of $12,500.

In a country where billions of dollars are siphoned off annually in corrupt oil deals and government contracts, the accusations against Mr. Haidari would seem to be minor: doling out bonuses of about $130 each to five employees. Reached Saturday on his cellphone, which his jailers allowed him to keep, Mr. Haidari said Prime Minister Nuri Kamal al-Maliki called him Friday evening and assured him that he had nothing to do with the arrest. But few people believe that to be the case.

Mr. Maliki has sought for two years to consolidate control over the electoral commission, whose independence is viewed as essential in ensuring that Iraqi elections are free from fraud, vote rigging and interference from political parties. Mr. Maliki’s critics say the effort is part of a pattern of power grabs — his near total takeover of the security forces, a recent attempt to exert influence over the central bank and politically motivated arrests under the pretext of thwarting coup plots. And it reinforces a narrative that Mr. Maliki is emerging as an authoritarian leader in the wake of the American military withdrawal.