Former President Barack Obama is poised to publicly throw his support behind Joe Biden after sitting out the early primary contests, according to news reports. Obama had declined to endorse his former vice president early in the process, preferring to let a record number of candidates duke it out for the Democratic nomination. CBS, which broke the news, said Obama would post a video message with his endorsement. The move would come a day after Bernie Sanders also endorsed Biden and ended his own bid for the White House.