The main Iraqi Kurdish parties remain on opposing sides in the continuing political battle over the shape of Iraq’s next government. The principal dividing line is between the Kurdistan Democratic Party (KDP) and the Patriotic Union of Kurdistan (PUK), whose rivalry in Baghdad is an extension of their longstanding disputes in Iraqi Kurdistan. This rift is now threatening to engulf the semi-autonomous region in a major political crisis.

The Kurdistan region of Iraq (KRI) is bracing to hold elections for its 111-member parliament on Oct. 1. The polls will be the sixth for the legislature since it was established in 1992. The KDP and its allies currently hold a 45-seat plurality in the body and have ambitions to expand their power both in Baghdad and Erbil...