A parliamentary vote for a new Iraqi president was delayed on Monday as the Kurds' two dominant parties for the first time contested the post reserved for a Kurd.
The election in Baghdad will now take place on Tuesday, two days after parliamentary polls in autonomous Iraqi Kurdistan and one year after the Kurds' ill-fated independence referendum.
The presidency has been reserved for the Kurds since Iraq's first multi-party elections in 2005, two years after the United States-led invasion that toppled dictator Saddam Hussein.
Under a tacit accord between the Kurdistan Democratic Party and the Patriotic Union of Kurdistan, the PUK would hold the federal presidency and the KDP the post of Iraqi Kurdistan's president.
The PUK's late Jalal Talabani served as federal president for eight years.
But the Iraqi Kurdish presidency has been left vacant since KDP leader Massud Barzani resigned at the end of his mandate following the September 2017 referendum he championed.
The KDP and PUK candidates for president of Iraq, where the prime minister is head of government, have been touring the south of the country to lobby for support and win the backing of deputies in the federal parliament.
The PUK's Barham Saleh, a 58-year-old moderate, has served in both administrations — as Iraqi deputy premier and Kurdish prime minister.
His rival for the post of president is the KDP's Fuad Hussein, a 72-year-old former chief of staff for Mr Barzani and a veteran of the opposition to Saddam.
Unlike most Kurds, he is a Shiite, a factor likely to win support from members of the Shiite-majority parliament.
On Monday, fewer than half of the deputies needed for a quorum showed up in parliament on time, forcing a new session to be scheduled for 2pm (UAE time) on Tuesday.
Under the constitution, if no candidate wins a two-thirds majority, the contest can be rerun on Tuesday or at a later date.
Iraq's parliament has chosen a speaker of the house but the post of prime minister has yet to be decided, more than four months after legislative elections.
In Iraq, the speaker of parliament is always a Sunni Arab, while the prime minister is Shiite and the president a Kurd.
Parliamentary coalitions — which bring together lists of Shiites, Sunnis and Kurds — must agree on the selection of the three positions.
Iraq's Kurds have been a key US partner in the war against ISIS and had hoped their role would boost international support for statehood.
But a massive "yes" vote in the referendum for independence, deemed illegal by Iraq's federal government and opposed by international powers, backfired drastically.
Baghdad imposed economic penalties and sent federal troops to push Kurdish forces out of oil fields vital for the region's economy, depriving it of a key lifeline.