What we know: After a few years off the front pages, 2011 will be a pivotal year for Sudan. As part of a 2005 peace agreement brokered by the United States to end the country's decades-long north-south civil war, Southern Sudan will vote in January on a referendum deciding whether to secede or remain part of Sudan. Most observers believe that the south will vote overwhelmingly for independence from Khartoum. An equal number of analysts, however, warn that the northern government won't let its southern half (particularly the lucrative oil deposits along the regional border) go without a fight. What we learn: In advance of the referendum, both north and south Sudan have long been rumored to be undertaking an intensive military build-up. A series of cables document the extent of those arrangements in the south, whose regional government in Juba has been importing arms from Ukraine via the government in Kenya. The transit route first came to light in September 2008, when a weapons shipment was seized by pirates off the coast of Somalia. The tanks aboard were said to be going to Kenya, but documentation suggested they may actually have been headed for "GOSS" (the Government of Southern Sudan). The suspicions were never substantiated and the cargo was delivered to Mombasa, Kenya. But an Oct. 8, 2008, cable confirms that the "33 Ukrainian T-72 tanks and other ammunition and equipment" aboard the seized vessel were indeed headed for Juba: Since last year, Kenya's Ministry of Defense has indeed played a major role in assisting the Government of South Sudan receive arms shipments from the Government of Ukraine. When the shipments are off-loaded at the port of Mombasa, they are transported via rail to Uganda and then onward to Southern Sudan (ref C). Military officials have expressed discomfort with this arrangement, however, and have made it clear to us that the orders come "from the top." (i.e., President Kibaki) The United States government raised the issue with the government of Ukraine, documented in another cable from November 2009, saying that the arms sales represented "deliberate Ukrainian government actions that are contrary to U.S. philosophy on [weapons] exports." The revelations stand to raise tensions in East Africa in the coming months. While support for Southern Sudan has long been forthcoming from Sudan's neighbors Kenya and Uganda, it has rarely been so explicit. The curveball: Sudan's neighbor, Uganda, blames Khartoum for paying and harboring Ugandan rebel Joseph Kony, leader of the Lord's Resistance Army (LRA), a brutal rebel group that has waged the longest-running insurgency in Africa. Ugandan President Yoweri Museveni told U.S. Assistant Secretary of State for African Affairs Jendayi Frazer in September 2007 that "Sudan, Sudan, Sudan, Sudan" was behind the rebellion's longevity. "[Museveni] said that even if the Khartoum Government could not supply the LRA at previous levels, he believed it was in constant touch with the LRA and smuggling supplies."