The legendary Kennedy clan endorsed US President Joe Biden during a campaign trip to Philadelphia Thursday -- underscoring the election threat posed by family black sheep and independent candidate Robert F. Kennedy Jr. "I don't want to become emotional, but what an incredible honor to have the support of the Kennedy family," Biden, 81, said after 15 members of politically storied family backed the Democrat against Donald Trump. That's right, the Kennedy family endorses Joe Biden for president," Kerry Kennedy said, referring to the family patriarchs.