Former U.S. President Barack Obama on Wednesday assailed his successor, Donald Trump, as deeply unfit for the office he occupies and argued that voting for his former No. 2, Joe Biden, was necessary to ensure the survival of American democracy. "He's shown no interest in putting in the work; no interest in finding common ground; no interest in using the awesome power of his office to help anyone but himself and his friends; no interest in treating the presidency as anything but one more reality show that he can use to get the attention he craves," Obama said of Trump during the third night of the Democratic National Convention.(Video courtesy: Democratic National Convention)