The Telegraph has an interesting, completely anecdotal article today suggesting that new immigrants are not necessarily voting Democrat and that they oppose amnesty for illegals. 

I tend to think this is true, but I'd note that the immigrants they interviewed are legal and had to wait a long time and go through a lot of hoops and expense to enter legally and attain the right of citizenship. The views of those who become citizens through amnesty programs may be different.  

The issue is not who'll get the most votes out of amnestied illegals but whether and how we should control our borders and protect national sovereignty, something BTW that Mexico seems to have mastered far better than we have.