GUEST: We live in an age where 85 percent of millennials in the U.S. have a smartphone, and they are fiddling with their apps 15 times a day. So you have to wonder: Why aren’t presidential candidates using mobile in their campaigns more effectively? With the 2016 presidential election in full swing, it’s critical for candidates to engage with voters – especially those between 18 and 29, who make up about one-fifth of voters and who have proven to be a valuable voting demographic.