You aren't giving Drumpf enough credit. He and his team polled conservatives and independents on many different topics before he came down the escalator in 2015. Immigration bashing was by far the most effective at getting people irrationally angry, and that's why he featured it from the beginning.
That's what I mean though - he didn't make the narrative, he polled around and found one he could work with. He was building on media demonization of immigrants for years
I disagree. The narrative was made by the conservative radio hosts and the people who make movies and the churches. Not by Trump. Trump just feeds it back to them. He didn’t even make up the birther stuff.