Feel free to go here:
http://www.onlinegamblingmythsandfacts.com/
to brush up on the BS arguments he may throw at you.
Also, mention the Antigua-WTO case and watch his blood boil.
If you could lead with Free Trade and then back into the Antigua-WTO case that would be great since I think he fancies himself a "free trader." He's ranking member of some agricultural sub-committee with constituents that benefit from the WTO.