Patrick Semansky/AP Photo; BIPresident Joe Biden vowed again on Wednesday that he is not dropping out of the race.If he does, Vice President Kamala Harris would start out as his best-positioned replacement.Harris has both practical and political benefits in her favor.Democrats would have a practical and political nightmare on their hands if President Joe Biden drops out and they decide to push Vice President Kamala Harris to the sidelines instead of the top of the ticket.On Wednesday, Biden and Harris jointly proclaimed to campaign aides that they would press on in the face of growing criticism following Biden's disastrous debate, according to the Associated Press."I am running.