When U.S. forces departed Iraq at the end of 2011, they left behind unresolved problems relating to that country's governance, notably concerning the relationship between the federal authority in Baghdad and the autonomous Kurdistan Regional Government (KRG) in the north. Today, disputes over the territorial delineation of the KRG remain a source of tension, while the discovery of significant reserves of oil and gas within and straddling the borders of the KRG has raised the stakes. Tensions have been heightened still further by the determination of the KRG authorities to pursue an energy policy independent of the central government. This has involved entering into lucrative energy exploration and exploitation agreements with a number of major energy companies, among them the U.S.-based ExxonMobil and Chevron, and moving ahead with an energy partnership with neighboring Turkey involving the construction of direct pipelines across their shared border.