If another Bush gets the Republican nomination I'm going to start believing conspiracy theories.
I think Rand would be by far the best choice. He has been said to be part of the open border crowd, since he leans toward Libertarian philosophy, and that's where that party is. So I copied the position on the issue given on his website and am pasting it here. At least from what he says he does not appear to be in favor of open borders:
"I do not support amnesty, I support legal immigration and recognize that the country has been enriched by those who seek the freedom to make a life for themselves. However, millions of illegal immigrants are crossing our border without our knowledge and causing a clear threat to our national security. I want to work in the Senate to secure our border immediately. In addition, I support the creation of a border fence and increased border patrol capabilities.
Immigrants should meet the current requirements, which should be enforced and updated. I realize that subsidizing something creates more of it, and do not think the taxpayer should be forced to pay for welfare, medical care and other expenses for illegal immigrants. Once the subsidies for illegal immigration are removed, the problem will likely become far less common.
I support local solutions to illegal immigration as protected by the 10th amendment. I support making English the official language of all documents and contracts.
Millions crossing our border without our knowledge constitutes a clear threat to our nation's security. Instead of closing military bases at home and renting space in Europe, I am open to the construction of bases to protect our border."
His position on 2A is the best out of the bunch, so I didn't see any need to go into detail on it.