President Trump wants to build a wall on the border between Mexico and the US. A wall to inhibit illegal Mexican migrants from trespassing into the US as they please. Basically, a wall to prevent migrants from Latin America in general. 

The irony of it all is that only about 0.9% of the country's population could "safely" be regarded as non-immigrants. These are the Amerindians, the Alaskan Inuits and Aleuts, and the Hawaiian Polynesians.

http://www.ugoupdatesng.com/2017/04/a-world-of-immigrants.html?m=1