evidence: The Obama administration signaled early on that it would be ready to engage Pyongyang, but North Korea’s multiple missile tests—followed by a nuclear test in May 2009—compelled the United States to push for tougher sanctions at the UN Security Council. The North continued its belligerence throughout 2010, sinking a South Korean navy ship and revealing a new uranium enrichment facility and light-water reactor at Yongbyon. It also shelled the South Korean island Yeonpyeong. [...] North Korea: The regime seeks a nonaggression security pledge from the United States, which deploys 28,500 troops in South Korea and maintains a heavy naval presence in the Pacific. Pyongyang also wants normalized relations with Washington and access to economic aid from other Six Party countries.