Power spent 2005–06 working in the office of U.S. Senator Barack Obama as a foreign policy fellow, where she was credited with sparking and directing Obama's interest in the Darfur conflict. She served as a senior foreign policy adviser to Obama's 2008 presidential campaign, but resigned during the primaries. In 2009 President Obama appointed her to a position on the National Security Council and in 2013 he appointed her as U.S. Ambassador to the United Nations, a cabinet-rank position.