WASHINGTON – President Donald Trump stood before a crowd in a state that had once been firmly in his grasp. That moment Wednesday in Iowa, a state Trump won comfortably four years ago but is now seen as competitive, underscored a fundamental challenge facing his reelection campaign: It’s not 2016. The president’s attempts to recycle attacks he used on Hillary Clinton that year have so far failed to effectively damage Democrat Joe Biden. “The president’s message is clear: he has accomplished more for America in 47 months than Joe Biden has in 47 years,” said Trump campaign communications director Tim Murtaugh. “This boils down to a choice between a political outsider who has shaken up Washington and a failed career politician.”The Trump campaign believes it has a viable, if narrow path to victory.