The wall was a mnemonic device to keep Trump focused--plain and simple. And now this is happening.

Trump is shutting down the government solely because of a concept dreamed up by Stone and Nunberg, and approved by Bannon, to keep their scatterbrained boss on task.

Inside Trump’s circle, the power of illegal immigration to manipulate popular sentiment was readily apparent, and his advisers brainstormed methods for keeping their attention-addled boss on message. They needed a trick, a mnemonic device. In the summer of 2014, they found one that clicked. “Roger Stone and I came up with the idea of ‘the Wall,’ and we talked to Steve [Bannon] about it,” said Nunberg. “It was to make sure he talked about immigration.”

Initially, Trump seemed indifferent to the idea. But in January 2015, he tried it out at the Iowa Freedom Summit, a presidential cattle call put on by David Bossie’s group, Citizens United. “One of his pledges was, ‘I will build a Wall,’ and the place just went nuts,” said Nunberg. Warming to the concept, Trump waited a beat and then added a flourish that brought down the house. “Nobody,” he said, “builds like Trump.”

https://www.bloomberg.com/news/articles/2018-12-20/the-guy-who-thought-up-the-wall-says-trump-should-shut-government-to-fund-it

The government is being shut down because of a concept that Sam Nunberg and Roger Stone came up with to keep Trump from getting distracted. Literally. And I think that's at least as important to remind the public of as it is to discuss whether Trump is slamming tables or being calm and polite.