and i think that should give you some sense of the president's view of vice president biden's aptitude for the top job. >> will you say right now that the president will or will not endorse somebody before the primary is over? >> i wouldn't speculate at this point about whether or not the president would offer an endorsement. >> so there's no possibility he could, say, endorse joe biden or endorse hillary clinton? >> i wouldn't rule out an endorsement. >> or bernie sanders. >> or bernie sanders. i wouldn't rule out the possibility of an endorsement of the democratic primary. >> the question now is should democrats be rooting for joe biden to get into the race? we'll talk about that next.