From the article:
So in many ways, I'm pretty moderate and mainstream. I'm not radical either way. I don't want to put tanks and shoot illegal immigrants as they come over, that's one extreme. The other is totally open borders—just let them flow in.
So he's not for open borders. He cites Canada as an example where edit: somewhat open borders have worked, but he says it is the job of the federal government to secure the borders. He wouldn't change immigration quotas and if we enforced the laws on the books that would be a huge step in the right direction. Compared to the stances of just about every other candidate who is for amnesty one way or another I would think he would win points for that.