Former Vice President Joe Biden said Thursday that he won’t promise to serve just one presidential term because of his advanced age but pledged that he would not seek a second if he loses “energy and mental acuity.” “Look, I guarantee you this: if anything changed in my health making incapable for me to fully exert all the energy and mental acuity that was needed to be done, I give you my word I would not run again,” Biden, 77, told a CNN town hall. “It’s totally legitimate for y’all to ask about my age or anybody else’s age up...