Robert F Kennedy Jr has dismissed Donald Trump as “unhinged” after a social media tirade from the former Republican president accused the independent White House hopeful of being a “Democrat plant” and “wasted protest vote”. “When frightened men take to social media they risk descending into vitriol, which makes them sound unhinged,” Kennedy wrote Saturday on X in a post that doubled as a debate challenge. “President Trump’s rant against me is a barely coherent barrage of wild and inaccurate claims that should best be resolved in the American tradition of presidential debate.”