The Kurds of Iraq are about to vote for independence and Baghdad is not happy.

Iraq is prepared to intervene militarily if the Kurdish region’s planned independence referendum results in violence, Prime Minister Haider al-Abadi told The Associated Press in an exclusive interview Saturday.
If the Iraqi population is “threatened by the use of force outside the law, then we will intervene militarily,” he said.
Iraq’s Kurdish region plans to hold the referendum on support for independence from Iraq on Sept. 25 in three governorates that make up their autonomous region, and in disputed areas controlled by Kurdish forces but which are claimed by Baghdad.

The Iraqi army marching into Kurdistan would not be something new.

Iraq's parliament rejected the Kurdish referendum, and then removed the governor of Kurdish-controlled Kirkuk from office.
And then things got serious.

Turkey on Thursday welcomed an Iraqi parliament move to reject a referendum on Kurdish independence.
The parliament in Baghdad authorized the prime minister to “take all measures” to preserve Iraq’s unity in response to the move to hold an independence referendum in Iraq’s semi-autonomous Kurdish region on Sept. 25.
Kurdish leader Massoud Barzani vowed to press ahead with the vote, calling it “a natural right”.
“Barzani’s referendum decision is a historic mistake. Turkey will follow policies that take Iraq’s territorial integrity as a basis,” Deputy Prime Minister Bekir Bozdag said.

Unlike every other time, the outcome of this conflict is not certain.
The Iraqi Kurds have never been stronger, while Baghdad has never been weaker.
The Iraqi Army never fully recovered from its 2014 collapse, and what parts that were rebuilt were chewed up in the Battle of Mosul.

That doesn't mean Baghdad has no army on it's side.

The Iraqi army and Hashid al-Shaabi (Popular Mobilization Units) have sent more troops to the town of Amerli, southwest of Tuz Khurmatu, a Peshmerga commander said.
...Mahmoud Sangawi, the head of Peshmerga forces at the Garmaser front and a member of the Patriotic Union of Kurdistan (PUK) Politburo, said on Friday (September 8) that Arabs in Mandali threatened they would attack Kurds if the referendum was carried out.

A Kurdish independence vote would likely be followed with an invasion by Shia militias.