I'm not american but it's clear who he should choose.
But personally i think the wrong democratic nominee won, Hillary should've taken it cause really she's the one who's got the most newest voters into the party. All he got was the youth vote who are unreliable when it comes to voting, and she's got the most experience to boot along with the popular vote and won ALL of the big states which is important in an election.
So the voters were stupid to bring him in, not to mention racist is still huge in the states and that'll probably cost the democrats the election if he doesn't bring Hillary in since she got the women and old white people vote.
Even the polls have them at a virtual tie...proving he aint no shoe-in. He may give a fine good speech, but bring someone else in to debate him, he's a scared puppy. and dealing with leaders is what the president always does.