A border wall is one off the top fundraising topics for the Trump campaign leading into 2020.
Trump’s spending in early 2019 was more than the Democratic campaigns combined, but he has been out-spent by some candidates in recent weeks.
This tends to underscore this is at least as much a symbolic and political fight as one looking for an effective approach.
Articles like this one show it has become a litmus issue for those who describe themselves as conservative.
As a separate item, I’ve created a page that looks for candidate positions on immigration and particularly the border wall.
Meanwhile, this article from Time further discusses some of the politics here.
This article describing some of the facebook ads