"...a probe into a letter sent to Hispanic voters claiming it is illegal for immigrants to vote."
I DOUBT if it said that. It probably said it is illegal for illegal immigrants or aliens to vote, since NBC chose to describe what it said rather than quote it honestly. But, it'll give Sanchez a boost, which is the point of the lefty hype.
From the other thread, I believe these are the problematic sentences: "You are advised that if your residence in this country is illegal or you are an immigrant, voting in a federal election is a crime that could result in jail time and you will be deported for voting without having a right to do so." and "At the same time, you are advised that the government of the United States is installing a new computer system to verify the names of all new registered voters that vote in the October and November elections. Anti-immigration organizations can ask for information from this new computer system." (According to the OC Register, there isn't such a system.)
The beginning sentences do encourage citizens to vote.
I believe that in legalese an "immigrant" is not allowed to vote. A "naturalized citizen" is allowed to vote. "Immigrant" refers to documented and undocumented aliens, neither of which can legally vote. I may be wrong on this, but I think I have the correct terms.