The dispute over the Abyei region is the most volatile aspect of Sudan’s 2005 Comprehensive Peace Agreement (CPA) and risks unravelling that increasingly shaky deal. The CPA granted the disputed territory, which has a significant percentage of Sudan’s oil reserves, a special administrative status under the presidency and a 2011 referendum to decide whether to join what might then be an independent South. However, in violation of the CPA, the ruling National Congress Party (NCP) is refusing the “final and binding” ruling of the Abyei Boundary Commission (ABC) report, leaving an administrative and political vacuum. Negotiations between the NCP and the former rebel Sudan People’s Liberation Army/Movement (SPLA/SPLM) are stalled, and both sides are building up their military forces around Abyei. The SPLM’s 11 October decision to suspend its participation in the Government of National Unity in protest of the NCP’s non-implementation the CPA, marks the most dangerous political escalation since the peace deal was signed. The international community needs to re-engage across the board on CPA implementation but nowhere more urgently than Abyei, where the risks of return to war are rising.