An important letter was delivered to Iraqi Foreign Minister Fuad Hussein last week. In a Jan. 24 meeting, US Ambassador Alina Romanowski carried a message from the Joe Biden administration seemingly addressed not only to the Iraqi government, but its domestic and regional supporters too. Officials have so far refrained from divulging details about the content of the letter. However, speaking on condition of anonymity, a senior Iraqi diplomatic source told Amwaj.media that the correspondence revolved around three key points.

First, the Biden administration is said to have signaled that it does not object to announcing an end to the international mission to fight the Islamic State group (IS). This matters because such a move would compel a redefinition of the strategic relationship between Baghdad and Washington.

Second, the senior Iraqi source told Amwaj.media, the letter underscored that a US military withdrawal from Iraq depends on...