A) More than 44,000 deaths would be prevented annually (as estimated recently in The New England Journal of Medicine).
B) About 150,000 deaths per year would be prevented annually (as estimated by the New York City Department of Health and Mental Hygiene).
C) Hundreds of millions of people would be subjected to an experiment with unpredictable and possibly adverse effects (as argued recently in The Journal of the American Medical Association).
D) Not much one way or the other.
E) Americans would get even fatter than they are today.
According to this article, there is no right answer, because the evidence is so conflicting.
So what should we do about salt intake? See this post from a couple weeks ago for the answer.
And PS: Here is a "Room for Debate" article from the NY Times seeking answers from several prominent food folks. Interesting.