There is a question about the legal basis on which US forces can remain without the permission of the Iraqi government

Guardian:

Washington is not willing to bow to Iraqi demands to withdraw its troops and any future discussions with Baghdad will be purely confined to the future structure of its forces in the country, the US State Department has said.

The recommitment to US troops in Iraq defies an Iraqi parliament vote last week demanding all US forces leave in the wake of the killing of the Iranian general Qassem Suleimani by a drone strike in Baghdad. The US secretary of state, Mike Pompeo, said the US was only willing to discuss force reconfiguration with the Iraqis, and a greater contribution by Nato forces.

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Earlier this week, Donald Trump threatened to impose economic sanctions on Iraq if it refused to house US troops, and said Iraq would be required to pay for the cost of any US troop withdrawal.

But Washington appears to have resolved it will not serve US strategic interests to quit on any terms at present, even though there is a question about the legal basis on which US forces can remain without the permission of the Iraqi government.