Word is circulating that Stephen Miller is writing Donald Trump's speech on race relations. I'm going to go out on a limb and predict that Trump's "solution" to the current malaise in the U.S. will involve extending a ban on immigration and expanding enforcement and expulsion of undocumented individuals. This seems like a safe bet to me because Miller really is a one-trick pony and Trump relishes rehashing his greatest hits. Maybe Miller will toss in some "enterprise zones" or other ornamental trivia but the meat will be anti-immigration.
They playbook for this will be Miller's Immigration Handbook for a New Republican Majority that he wrote for Jeff Sessions in 2015. Footnote 21 of that handbook states that, "Amnesty and uncontrolled immigration disproportionately harms African-American workers, and has been described by U.S. Civil Rights Commission member Peter Kirsanow as a 'disaster.'" The handbook also cites a poll commissioned by Kellyanne \Conway, one finding of which was that "86% of black voters and 71% of Hispanic voters said companies should raise wages and improve working conditions instead of increasing immigration."
Two years ago, I posted a couple of pieces discussing Miller's handbook in more detail: The Lump That Begot Trump and Goebbels or Gompers?: A Closer Look at Stephen Miller's Immigration Manifesto. I hope these pieces provide some insight into just how dangerous and effective Miller's and Trump's anti-immigration rhetoric can be, especially given the hypocrisy of neo-liberal promotion of immigration as exemplified by Tony Blair's and Gerhard Schroeder's "Third Way" advocating "a new supply-side agenda for the left". To put it bluntly, "Third Way" immigration policy was intended to create jobs by keeping wages low through an abundant supply of labor. The transfer of income from the working class to the wealthy would provide ample funds for "investment."
In short, Miller's and Trump's anti-immigrant rhetoric is dangerous and effective because Blair and Schroeder (and Clinton and Obama) enacted right-wing, supply-side economic policies in the name of "the ['responsible'] left."