Washington (AFP) – The most polarized US election in decades was on a knife-edge Tuesday as President Donald Trump appeared to have held off predictions of a sweeping Democratic wave but Joe Biden also scored key wins.Against a backdrop of the Covid-19 pandemic that has claimed more than 230,000 lives in the United States, a quick Biden triumph — dreamed of by some Democrats — looked unlikely with key states too close to call.Trump enjoyed a slim but vital lead in Florida, widely considered a must win to retain the presidency, despite opinion polls that had shown Biden edging even or ahead.”…