In a nutshell, since he's a supporter, I'd ask 'Given the obvious economic advantages industrial hemp would provide our states/country, what obstacles stand in the way of a major hemp bill being passed? And how do we, as citizens and representatives, combat these obstacles?'
Kind of the same as 'what is Congress afraid of' and 'wouldn't it help our job market'... but more directly places the issue on his lap. IMO likely get a more pointed response. And I'd love to hear it.
:)
TM