The way I see it, when one says "let us go, you and I", the second clause
qualifies the first. I feel that many people are making the mistake of
thinking of the two clauses as being inherently interchangeable, when
they're not -- in other words, thinking that the correct usage is that
which we would get if we were to interpolate the second clause into the
first - "let me go", rather than "let I go". But that's not correct --
rather, we should think of it as: "Let us go". "Who is going?" "You and I
Just my ill-described tuppence.