Vice President Joe Biden said he is overwhelmed at times by his son’s death and unconvinced he could commit fully to being president, in an emotional interview that cast a deep pall over his deliberations about the 2016 presidential race.

Asked about his 2016 decision on CBS’ “The Late Show,” Biden said Thursday he’d be lying if he said he knew he was prepared to run following Beau Biden’s death in May to brain cancer. With a level of candor seen rarely in politics, he recalled a breakdown of his emotions during a recent visit to a Colorado military base when a well-wisher yelled out the name of his son and referenced his decorated military service in Iraq.