This is the guy who helped make Donald Trump possible

NationBuilder lets politicians use a template for electoral success and find out what voters want, writes Adam Satariano

IN LATE January, Donald Trump held one of his final rallies before the Iowa caucuses at the Dubuque airport.

On the tarmac, with loudspeakers blasting the theme from the Harrison Ford movie Air Force One, a crowd of shivering supporters roared when Trump’s Boeing 757 made a flyby. Many of the estimated 400 people in attendance had been notified about the event through NationBuilder, a digital hub for campaigns that handles website design, fundraising, organising volunteers, and social media.