I'm very leary of FIJA's motives. I think they are

actually trying to deliver the message that it is a juror's duty to not judge solely thru their conscience, but rather thru what is constitutional. In other words (and this is what I believe FIJA is emphasizing) It is a juror's duty to determine if the law for which the accused is being tried of breaking, is a law that is in conflict with what the constitution says is legal or illegal, and to therefor ecast there vote accordingly.
Anyways; that's what I got out of their literature.

But if I was a juror, I wouldn't give a fuck whether the constitution said this or that is legal to do or say, but would rather cast my vote according my own good sense as to whether I thought the law was a just one or not.

Fuck the constitution.
I would cast my vote according to what I myself (independant of the constitution or current laws) felt was right.