WASHINGTON -The enormous cache of secret war logs disclosed by the WikiLeaks website paints a picture of an Iraq burdened by persistent sectarian tension and meddling neighbors, suggesting that the country could drift into chaos once U.S. forces leave. The reports, covering early 2004 to Jan. 1, 2010, help explain why Iraq's struggle to create a unified, independent state continues, despite a dramatic reduction in violence. They appear to support arguments by some experts that the U.S. should keep thousands of troops there beyond their scheduled departure in 2011, to buy more time for Iraq to become stable. The threats...