IMHO it is Steve Stockman. See this article: http://www.freerepublic.com/focus/f-news/3110006/posts
He exposed Cornyn’s support for expanding the definition of “mentally incompetent” for purposes of the NICS background check. Cornyn apparently likes the idea of denying people an explicitly stated and guaranteed Constitutional right - FOR LIFE, and with no possibility of appeal.
Thanks. Stockman will get my vote.