Stopillegalimmigration said:

NumbersUSA already raised Trump's grade after he walked back his amnesty comments.
They raised him from harmful to mixed (still not good enough IMO). He did not fully walk back his amnesty talk, just revised it somewhat. He is still saying the "good ones" will be offered an expedited return, which means they'll be placed in front of the immigration line and processed quickly. That is amnesty. Of course he hasn't told us yet what he considers good ones and bad ones. Well, he'll probably change that again in the next few days. There is no denying that the man has been jumping all over the place on the issue.

Only 2 candidates are tougher than Trump on immigration and neither have momentum and support that Trump has!
I agree that Santorum and Scott don't currently have the support that Trump does. However, that is subject to change because it is still early in the process. Walker seems to be holding his own and has consistently been polling in the top three. That's not a bad place to be at this early stage of the game.

Remember Trump can still toughen his position on immigration before he gets to the White House!
I guess that could be said for every single candidate.