WASHINGTON — A White House official said President Barack Obama will name former aide Samantha Power as the U.S. ambassador to the United Nations, reported the Associated Press.

Power will replace Susan Rice, who will take over as Obama’s national security adviser. The official says Obama will announce both appointments from the White House Wednesday afternoon, according to AP.

Power is a longtime Obama adviser who worked on his 2008 presidential campaign and ran the human rights office in the White House. She left the administration in February but was considered the favorite to replace Rice at the U.N.

Power played an instrumental role in getting Sen. Obama to issue a strongly-worded statement on the Armenian Genocide and Armenian issues in general. She also made a video in which she recounted Sen. Obama’s outstanding record on issues of special concern to Armenian Americans, including his “very forthright statement on the Armenian Genocide; his support for the Senate Resolution acknowledging the Genocide; his willingness as President to commemorate it and call a ’spade a spade’; and to speak the truth about it.”

A video plea to the Armenian-American community during the 2008 Obama campaign became a rallying tool for Armenians to support the then senator from Illinois. However, Power failed to deliver—just as the Obama Administration—on her pledge to get US recognition of the Armenian Genocide.

In 2003, the Pulitzer Prize in literature for the best general non-fiction book was awarded to Samantha Power for her book “A Problem from Hell: America in the Age of Genocide.”

Power’s book revisited the Armenian Genocide–the Holocaust–Cambodia’s Khmer Rouge–Iraqi attacks on Kurdish populations–Rwanda–and Bosnian ethnic cleansing. Power makes a compelling argument that US intervention in all these instances of genocide has been inadequate.