BEIJING (AP) — China took a step against longtime ally North Korea on Tuesday by voting in favor of a U.N. Security Council resolution condemning Pyongyang’s long-range rocket launch in December. Beijing is concerned that North Korea’s nuclear ambitions are destabilizing the region, but is willing to go only so far to punish its economically struggling neighbor. Here are some questions and answers about China’s role:

WHY DOES CHINA SUPPORT NORTH KOREA?