Former President Donald Trump’s outspoken followers are unwittingly helping his political foe in the upcoming presidential debate by bombarding President Joe Biden with insults about his age, according to The Guardian political columnist Margaret Sullivan. Conservative’s constant attacks on Biden’s mental sharpness have only succeeded in easing the criteria for success the 81-year-old incumbent must meet when he faces off against Trump on CNN Thursday night, Sullivan argues. “Biden may make some missteps in the debate, but he’ll be well prepared and focused on appearing vigorous, as he was in …