Dear Ken,

> p. 10 (+7) Perhaps explain why this is a concrete consequence,
> saying a little about J_0(Nl^2); also, the end of the line
> sticks out badly into the margin.

That this is a concrete consequence is explained in Section 3.1 of chapter 3.
Why does Brian want level Nl^2 instead of level Nl?

RIBET: If you want weights beyond l+1, then you have to twist
by powers of the cyclotomic character, which you view as a character
of conductor l.  That twisting raises level from ...l to ...l^2.
Whether Brian is right or not depends on the context -- were
high weights contemplated at that juncture?

WAS: -- YES -- It says:
   A concrete consequence of the conjecture is that all odd  
   irreducible 2-dimensional~$\rho$ come from abelian varieties 
   over~$\Q$.  Given~$\rho$, one should be able to find a totally 
   real or CM number field~$E$, an abelian variety~$A$ over~$\Q$  
   of dimension [...]

I now see why it is necessary to introduce ell^2.  However, 
I'm not sure we should explain further, at least at the late point
in the writing of the paper. 

*However* maybe we should mention "Theorem F" (page 4) of Taylor's amazing new 
paper "Remarks on a Conjecture of Fontaine and Mazur", which seems to prove the
above concrete consequence under a reasonable local hypothesis.   

William