 Even so, swing state voters did think Biden, as I mentioned, acquitted himself poorly in the debate itself with fewer than one in five respondents saying the 81-year-old appeared coherent, mentally fit or dominant. Biden, for his part, vowing to stay in the presidential race, telling ABC's George Stephanopoulos a higher power would have to tell him to bow out before he gives up. If you can be convinced that you cannot defeat Donald Trump, will you stand down?