BAGHDAD - Iran's influence is looming large as Iraqis prepare to head to the polls for parliamentary elections in May, with many in the country worried that Tehran may be looking to strengthen its political grip on Baghdad through the ballot box.
Iranian support and military advisers helped Baghdad's Shiite-led government beat back the Islamic State group. But with IS militants now largely defeated militarily, Iran's expanding influence has emerged as one of Iraq's most divisive issues ahead of the balloting.
That influence has sown fear among Iraq's disenchanted minority Sunnis, who bore the brunt of the war's destruction, and has also caused concern in Washington. Despite tensions between the United States and Iran, both remain key allies of Iraqi Prime Minister Haider al-Abadi's government.
U.S. Defence Secretary Jim Mattis last month accused Iran of "mucking around" in Iraq's upcoming elections, telling reporters the U.S. has what he called "worrisome evidence" that Iran is funneling "not an insignificant amount of money" into Iraq to try to sway votes. Baghdad rejected the accusation.
Government spokesman Saad al-Hadithi stressed that the use of foreign money in domestic politics "is illegal and unconstitutional."
"The government is taking great efforts to hold free and fair elections and prevent the manipulation of election results," he said.
Both Iran and Iraq are Shiite-majority counties and share deep economic and cultural ties — as well as a 1,500-kilometre (900-mile) border.
The two countries fought a devastating war in the 1980s that left hundreds of thousands dead. But Iranian influence in Iraq has steadily grown since the 2003 U.S.-led invasion that toppled Iraqi dictator Saddam Hussein, marking the start of a prolonged period of sectarian division, extremist violence and political strife.
Under Saddam, many of Iraq's Shiite political elite spent years in exile in Iran. Since Saddam's ouster, Iraqi markets have been stocked with Iranian goods and millions of Iranian pilgrims descend on Iraq each year to visit holy shrines in the cities of Samarra, Baghdad, Najaf and Karbala.
When entire divisions of Iraq's military disintegrated following the fall of the city of Mosul to IS in the summer of 2014, Iranian influence soared.
Weeks before the U.S. began a bombing campaign against IS, Iranian advisers and support for Iraqi Shiite militias, which became known as Popular Mobilization Units, helped halt IS' advance, which came dangerously close to Baghdad. From then on, the militias became instrumental in the battle against IS.
More than 500 members of the paramilitary forces or political figures associated with the militias are now running for parliament.
Ahmed al-Asadi is one of the candidates with strong paramilitary ties. An elected member of parliament from Baghdad and former spokesman for the PMU, al-Asadi cut his ties with the force before launching his re-election bid — a formality required by a governing body overseeing the May vote.
"Iran is the ally of the powerful forces that supported Iraq against terrorism," he said, dismissing concerns that Tehran plays a destabilizing role in Iraq.
But other Iraqi politicians worry that if a large number of men like al-Asadi win seats in parliament, Iraq will be even more beholden to its eastern neighbour.
Saleh al-Mutlaq, a longtime Iraqi politician and former deputy prime minister, said he expects candidates with ties to the Shiite militias to do well in upcoming elections.
"These elections will be disastrous for this country," he said. "The PMU will be a key player in the political process and this will give Iran a role and a word in forming the government and in choosing a prime minister."
Iran is not the only one trying to influence the May vote, said Joost Hiltermann, a longtime Iraq researcher with the International Crisis Group.
"Everybody is trying to buy or gain influence, anybody who has a stake in Iraq that is, whether they do it with money or intimidation or other kinds of incentives," he said. "Ever since there have been elections in 2005, there's been meddling."
The future of American forces in Iraq hinges in large part on who becomes Iraq's next prime minister and who gets to lead the country's most powerful ministries.
While the Shiite militias racked up several early victories against IS, it was U.S.-led coalition airstrikes that allowed Iraqi forces to retake urban areas. Iraq remains deeply dependent on U.S. military aid, training and intelligence sharing.
While al-Abadi, who is seeking re-election with his recently formed Victory Alliance party, has said he is open to long-term American training programs for Iraqi forces, some of his opponents have taken a much harder line, describing any U.S. forces in Iraq as occupiers.
The U.S. still has more than 5,000 troops in Iraq, supporting its fight against remaining pockets of IS, most significantly along Iraq's volatile border with Syria, in western Anbar province and around the city of Kirkuk — areas that have seen an uptick in militant activity.
"I'm not going to speculate on anything that could or would happen," coalition spokesman Col. Ryan Dillon said when asked if there is concern that a change in government could affect the U.S.-led coalition's presence in Iraq.
"We are here at the invitation of the government of Iraq to support their operation to defeat Daesh, and we'll continue to do so as long as we are invited," he said, referring to IS by an Arabic acronym.