Sanders, 74, is within striking distance of a monumental victory. Heading into the Iowa caucuses, the Independent senator from Vermont is trailing Clinton by just three points

IOWA CITY, IOWA—Khadidja Elkeurti is a liberal 17-year-old who thinks America “deserves” its first female president. She is volunteering for Bernie Sanders. Hillary Clinton, Elkeurti said in Iowa on Saturday, is a flip-flopper who voted for the invasion of Iraq and seems to be hankering for more war. Clinton, she added, wouldn’t fight for the middle…